Номер 33.4, страница 242 - гдз по физике 10-11 класс задачник Гельфгат, Генденштейн

Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета

Авторы: Гельфгат И. М., Генденштейн Л. Э., Кирик Л. А.

Тип: Задачник

Издательство: Илекса

Год издания: 2008 - 2026

Уровень обучения: профильный

Цвет обложки: красный лупа, парень едет на велосипеде

ISBN: 978-5-89237-252-7

Электродинамика. Электромагнитные колебания и волны. 33. Свободные электромагнитные колебания. Переменный ток. Упражнения - номер 33.4, страница 242.

App\Models\Task {#1030 // resources/views/models/task/default.blade.php
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                              "field_genitive_case" => "задачника"
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                              "field_prepositional_case" => "задачнике"
                            ]
                            "field_plural_form" => null
                            "field_short_name" => null
                            "field_short_name_foreign" => null
                            "field_translit" => "zadachnik"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1066
                      #items: array:1 [
                        0 => App\Models\Term {#1073
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 9
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Россия"
                            "field_cases" => array:6 [
                              "field_accusative_case" => null
                              "field_creative_case" => null
                              "field_dative_case" => null
                              "field_genitive_case" => null
                              "field_nominative_case" => null
                              "field_prepositional_case" => null
                            ]
                            "field_translit" => "rossiya"
                          ]
                          #original: array:6 [
                            "id" => 9
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Россия"
                            "field_cases" => array:6 [
                              "field_accusative_case" => null
                              "field_creative_case" => null
                              "field_dative_case" => null
                              "field_genitive_case" => null
                              "field_nominative_case" => null
                              "field_prepositional_case" => null
                            ]
                            "field_translit" => "rossiya"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1064
                      #items: array:1 [
                        0 => App\Models\Term {#1067
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 15
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Москва"
                            "field_cases" => array:6 [
                              "field_accusative_case" => null
                              "field_creative_case" => null
                              "field_dative_case" => null
                              "field_genitive_case" => null
                              "field_nominative_case" => null
                              "field_prepositional_case" => null
                            ]
                            "field_translit" => "moskva"
                          ]
                          #original: array:6 [
                            "id" => 15
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Москва"
                            "field_cases" => array:6 [
                              "field_accusative_case" => null
                              "field_creative_case" => null
                              "field_dative_case" => null
                              "field_genitive_case" => null
                              "field_nominative_case" => null
                              "field_prepositional_case" => null
                            ]
                            "field_translit" => "moskva"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1065
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1059
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1089
                      #items: array:1 [
                        0 => App\Models\Term {#1088
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 40
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "профильный"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "профильный"
                              "field_creative_case" => "профильным"
                              "field_dative_case" => "профильному"
                              "field_genitive_case" => "профильного"
                              "field_nominative_case" => "профильный"
                              "field_prepositional_case" => "профильном"
                            ]
                            "field_translit" => "profilnyy"
                          ]
                          #original: array:6 [
                            "id" => 40
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "профильный"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "профильный"
                              "field_creative_case" => "профильным"
                              "field_dative_case" => "профильному"
                              "field_genitive_case" => "профильного"
                              "field_nominative_case" => "профильный"
                              "field_prepositional_case" => "профильном"
                            ]
                            "field_translit" => "profilnyy"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1081
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1082
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1080
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => "лупа, парень едет на велосипеде"
                    "field_publication_year" => "2008"
                    "field_publication_year_until" => null
                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебное издание"
                    "field_allowed" => null
                    "field_reserve_field" => null
                    "field_link_to_source" => null
                    "field_tasks_count" => "459"
                    "field_priority" => null
                    "field_default_folder" => "/fizika_10/gelfgat-z/"
                    "field_isbn" => "978-5-89237-252-7"
                    "field_cover" => array:1 [
                      0 => "/media/fizika_10/gelfgat-z/covers/cover1.webp?ts=1756049816"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/fizika_10/gelfgat-z/covers/cover1.webp?ts=1756049816"
                        "alt" => ""
                        "width" => "1566"
                        "height" => "2412"
                      ]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1085
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1083
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1086
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1092
                      #items: array:1 [
                        0 => App\Models\Term {#1084
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 46
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "красный"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "красный"
                              "field_creative_case" => "красным"
                              "field_dative_case" => "красному"
                              "field_genitive_case" => "красного"
                              "field_nominative_case" => "красный"
                              "field_prepositional_case" => "красном"
                            ]
                            "field_translit" => "krasnyy"
                          ]
                          #original: array:6 [
                            "id" => 46
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "красный"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "красный"
                              "field_creative_case" => "красным"
                              "field_dative_case" => "красному"
                              "field_genitive_case" => "красного"
                              "field_nominative_case" => "красный"
                              "field_prepositional_case" => "красном"
                            ]
                            "field_translit" => "krasnyy"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "breadcrumbs" => array:3 [
                      "class" => 381
                      "subject" => 556
                      "class_subject" => 494
                    ]
                  ]
                  #original: array:50 [
                    "id" => 5400
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_tree_default_status" => "tasks"
                    "field_pages_status" => null
                    "field_subject" => Illuminate\Database\Eloquent\Collection {#1061}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1063}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1062}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1070}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1074}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1075}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1066}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1064}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1065}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1059}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1089}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1081}
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1082}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1080}
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => "лупа, парень едет на велосипеде"
                    "field_publication_year" => "2008"
                    "field_publication_year_until" => null
                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебное издание"
                    "field_allowed" => null
                    "field_reserve_field" => null
                    "field_link_to_source" => null
                    "field_tasks_count" => "459"
                    "field_priority" => null
                    "field_default_folder" => "/fizika_10/gelfgat-z/"
                    "field_isbn" => "978-5-89237-252-7"
                    "field_cover" => array:1 [
                      0 => "/media/fizika_10/gelfgat-z/covers/cover1.webp?ts=1756049816"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/fizika_10/gelfgat-z/covers/cover1.webp?ts=1756049816"
                        "alt" => ""
                        "width" => "1566"
                        "height" => "2412"
                      ]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1085}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1083}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1086}
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1092}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "breadcrumbs" => array:3 [
                      "class" => 381
                      "subject" => 556
                      "class_subject" => 494
                    ]
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1049
              #items: []
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1319339
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Электродинамика"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1047}
            "field_page_start" => "163"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1057}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1049}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1115
      #items: array:4 [
        0 => App\Models\Branch {#1125
          #connection: "mysql"
          #table: "branches"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:24 [
            "id" => 1319339
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Электродинамика"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1126
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "163"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1127
              #items: array:1 [
                0 => App\Models\Book {#1056}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1128
              #items: []
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1319339
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Электродинамика"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1126}
            "field_page_start" => "163"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1127}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1128}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        1 => App\Models\Branch {#1129
          #connection: "mysql"
          #table: "branches"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:24 [
            "id" => 1319371
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Электромагнитные колебания и волны"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1130
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "241"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1131
              #items: array:1 [
                0 => App\Models\Book {#1056}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1132
              #items: array:1 [
                0 => App\Models\Branch {#1045}
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1319371
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Электромагнитные колебания и волны"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1130}
            "field_page_start" => "241"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1131}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1132}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        2 => App\Models\Branch {#1133
          #connection: "mysql"
          #table: "branches"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:24 [
            "id" => 1319372
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "33. Свободные электромагнитные колебания. Переменный ток"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1134
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "241"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1135
              #items: array:1 [
                0 => App\Models\Book {#1056}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1144
              #items: array:1 [
                0 => App\Models\Branch {#1143
                  #connection: "mysql"
                  #table: "branches"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
                    "id" => 1319371
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Электромагнитные колебания и волны"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1145
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "241"
                    "field_branch_display" => "0"
                    "field_branch_expanded" => "0"
                    "field_display_branch_in_title" => "1"
                    "field_display_task_interval" => "0"
                    "field_display_branch_page" => "1"
                    "field_branch_title_in_content" => "0"
                    "field_navigation_title" => null
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "field_branch_cover" => []
                    "field_branch_covers" => []
                    "book" => Illuminate\Database\Eloquent\Collection {#1146
                      #items: array:1 [
                        0 => App\Models\Book {#1056}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1147
                      #items: array:1 [
                        0 => App\Models\Branch {#1045}
                      ]
                      #escapeWhenCastingToString: false
                    }
                  ]
                  #original: array:24 [
                    "id" => 1319371
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Электромагнитные колебания и волны"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1145}
                    "field_page_start" => "241"
                    "field_branch_display" => "0"
                    "field_branch_expanded" => "0"
                    "field_display_branch_in_title" => "1"
                    "field_display_task_interval" => "0"
                    "field_display_branch_page" => "1"
                    "field_branch_title_in_content" => "0"
                    "field_navigation_title" => null
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "field_branch_cover" => []
                    "field_branch_covers" => []
                    "book" => Illuminate\Database\Eloquent\Collection {#1146}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1147}
                  ]
                  #changes: []
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                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
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                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
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            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "33. Свободные электромагнитные колебания. Переменный ток"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1134}
            "field_page_start" => "241"
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            "field_display_branch_in_title" => "1"
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            "field_navigation_title" => null
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            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1135}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1144}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        3 => App\Models\Branch {#1137
          #connection: "mysql"
          #table: "branches"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:24 [
            "id" => 1319373
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Упражнения"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1136
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "241"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1140
              #items: array:1 [
                0 => App\Models\Book {#1056}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1153
              #items: array:1 [
                0 => App\Models\Branch {#1152
                  #connection: "mysql"
                  #table: "branches"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
                    "id" => 1319372
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "33. Свободные электромагнитные колебания. Переменный ток"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1154
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "241"
                    "field_branch_display" => "0"
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                    "field_h1" => null
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                    "field_description_bottom" => null
                    "field_branch_cover" => []
                    "field_branch_covers" => []
                    "book" => Illuminate\Database\Eloquent\Collection {#1155
                      #items: array:1 [
                        0 => App\Models\Book {#1056}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1156
                      #items: array:1 [
                        0 => App\Models\Branch {#1143}
                      ]
                      #escapeWhenCastingToString: false
                    }
                  ]
                  #original: array:24 [
                    "id" => 1319372
                    "created_at" => "2026-04-10 13:58:26"
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                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1154}
                    "field_page_start" => "241"
                    "field_branch_display" => "0"
                    "field_branch_expanded" => "0"
                    "field_display_branch_in_title" => "1"
                    "field_display_task_interval" => "0"
                    "field_display_branch_page" => "1"
                    "field_branch_title_in_content" => "0"
                    "field_navigation_title" => null
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "field_branch_cover" => []
                    "field_branch_covers" => []
                    "book" => Illuminate\Database\Eloquent\Collection {#1155}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1156}
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1319373
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Упражнения"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1136}
            "field_page_start" => "241"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1140}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1153}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "content" => Illuminate\Database\Eloquent\Collection {#1038
      #items: array:2 [
        0 => App\Models\Element {#1106
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:7 [
            "id" => 1493935
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1096
              #items: array:1 [
                0 => App\Models\Edition {#1105
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:21 [
                    "id" => 5430
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Условие"
                    "field_order" => "1"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1102
                      #items: array:1 [
                        0 => App\Models\Term {#1104
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 5158
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Илекса"
                            "field_cases" => null
                            "field_translit" => "ileksa"
                          ]
                          #original: array:6 [
                            "id" => 5158
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Илекса"
                            "field_cases" => null
                            "field_translit" => "ileksa"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_content_type" => "free"
                    "field_content_mode" => "text, image"
                    "field_page_content_mode" => "image"
                    "field_content_text_checked" => null
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Автор"
                    "field_moderator" => "stas"
                    "field_edition_type" => "statement"
                    "field_root_dir" => "0-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1103
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1101
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_process_formula" => "katex"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1100
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_content_source" => null
                  ]
                  #original: array:21 [
                    "id" => 5430
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Условие"
                    "field_order" => "1"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1102}
                    "field_content_type" => "free"
                    "field_content_mode" => "text, image"
                    "field_page_content_mode" => "image"
                    "field_content_text_checked" => null
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Автор"
                    "field_moderator" => "stas"
                    "field_edition_type" => "statement"
                    "field_root_dir" => "0-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1103}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1101}
                    "field_process_formula" => "katex"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1100}
                    "field_content_source" => null
                  ]
                  #changes: []
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                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
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                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "1319784"
              "type" => "task"
            ]
            "text" => "<p><strong>33.4.</strong> Найдите действующее значение $\text{I}$ переменного тока (см. рис. а, б, в).</p><p><em><strong>Решение.</strong></em> Величина $\text{I}$ представляет собой значение силы постоянного тока, при прохождении которого в проводнике выделяется такое же количество теплоты, как и при прохождении данного переменного тока за это же время (т. е. $I^2 = \overline{i^2}$).</p><p><strong>а)</strong> Квадрат силы тока в любой момент равен $I_0^2$. Поэтому $I = I_0$.</p><p><strong>б)</strong> $I^2 T = I_0^2 \cdot \frac{T}{8} + (-I_0)^2 \cdot \frac{T}{8}$, откуда $I = I_0/2$.</p><p><strong>в)</strong> $I^2 T = I_0^2 \tau$, откуда $I = I_0 \sqrt{\frac{\tau}{T}}$.</p>"
            "img" => array:1 [
              0 => array:5 [
                "name" => "4-1.jpg"
                "alt" => null
                "width" => "1408"
                "height" => 1178
                "path" => "/media/fizika_10/gelfgat-z/0-33/4-1.webp?ts=1756251143"
              ]
            ]
          ]
          #original: array:7 [
            "id" => 1493935
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1096}
            "task" => array:2 [
              "refs" => "1319784"
              "type" => "task"
            ]
            "text" => "<p><strong>33.4.</strong> Найдите действующее значение $\text{I}$ переменного тока (см. рис. а, б, в).</p><p><em><strong>Решение.</strong></em> Величина $\text{I}$ представляет собой значение силы постоянного тока, при прохождении которого в проводнике выделяется такое же количество теплоты, как и при прохождении данного переменного тока за это же время (т. е. $I^2 = \overline{i^2}$).</p><p><strong>а)</strong> Квадрат силы тока в любой момент равен $I_0^2$. Поэтому $I = I_0$.</p><p><strong>б)</strong> $I^2 T = I_0^2 \cdot \frac{T}{8} + (-I_0)^2 \cdot \frac{T}{8}$, откуда $I = I_0/2$.</p><p><strong>в)</strong> $I^2 T = I_0^2 \tau$, откуда $I = I_0 \sqrt{\frac{\tau}{T}}$.</p>"
            "img" => array:1 [
              0 => array:5 [
                "name" => "4-1.jpg"
                "alt" => null
                "width" => "1408"
                "height" => 1178
                "path" => "/media/fizika_10/gelfgat-z/0-33/4-1.webp?ts=1756251143"
              ]
            ]
          ]
          #changes: []
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          #attributeCastCache: []
          #dateFormat: null
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            "text" => "<p><strong>Дано:</strong></p><p>Графики зависимости мгновенной силы тока $i$ от времени $t$ для трех случаев (рис. а, б, в).</p><p>Амплитудное значение тока: $I_0$.</p><p>Период тока: $T$.</p><p>Длительность импульса для случая в: $\tau$.</p><p><strong>Найти:</strong></p><p>Действующее значение переменного тока $I$ для каждого случая.</p><p><strong>Решение:</strong></p><p>Действующее (или эффективное) значение переменного тока $I$ определяется как значение такого постоянного тока, который за время, равное периоду переменного тока, выделит в проводнике то же количество теплоты, что и данный переменный ток. Квадрат действующего значения $I^2$ равен среднему значению квадрата мгновенной силы тока $i^2$ за период $T$. Это значение вычисляется по формуле:</p><p>$I^2 = \overline{i^2} = \frac{1}{T} \int_0^T i(t)^2 \, dt$</p><p>Соответственно, действующее значение тока равно $I = \sqrt{\overline{i^2}}$.</p><p>Рассчитаем действующее значение тока для каждого из трех представленных случаев.</p><p><strong>а)</strong></p><p>На графике (рис. а) изображен переменный ток прямоугольной формы (меандр). В течение первой половины периода ($0 \le t &lt; T/2$) сила тока равна $I_0$, а в течение второй половины ($T/2 \le t &lt; T$) — $-I_0$.</p><p>Квадрат мгновенного значения силы тока $i^2$ остается постоянным в течение всего периода:</p><p>Если $i = I_0$, то $i^2 = I_0^2$.</p><p>Если $i = -I_0$, то $i^2 = (-I_0)^2 = I_0^2$.</p><p>Таким образом, среднее значение квадрата силы тока за период равно самому этому значению:</p><p>$I^2 = \overline{i^2} = I_0^2$</p><p>Отсюда находим действующее значение тока:</p><p>$I = \sqrt{I_0^2} = I_0$</p><p><strong>Ответ:</strong> $I = I_0$.</p><p><strong>б)</strong></p><p>На графике (рис. б) изображен ток в виде последовательности разнополярных импульсов. Согласно приведенной в задании формуле для решения, будем считать, что за один период $T$ ток принимает значение $I_0$ в течение общего времени $T/8$, значение $-I_0$ в течение общего времени $T/8$, а в остальное время он равен нулю.</p><p>Найдем среднее значение квадрата силы тока за период $T$, используя определение:</p><p>$I^2 = \frac{1}{T} \int_0^T i(t)^2 \, dt$</p><p>Поскольку ток отличен от нуля только в определенные промежутки времени, интеграл можно разбить на части. Общее количество тепла за период $T$ пропорционально $I^2T$. Это же количество тепла выделяется переменным током:</p><p>$I^2 T = I_0^2 \cdot \frac{T}{8} + (-I_0)^2 \cdot \frac{T}{8}$</p><p>Упростим выражение:</p><p>$I^2 T = I_0^2 \frac{T}{8} + I_0^2 \frac{T}{8} = I_0^2 \frac{2T}{8} = I_0^2 \frac{T}{4}$</p><p>Сократив на $T$, получим:</p><p>$I^2 = \frac{I_0^2}{4}$</p><p>Действующее значение тока равно:</p><p>$I = \sqrt{\frac{I_0^2}{4}} = \frac{I_0}{2}$</p><p><strong>Ответ:</strong> $I = I_0/2$.</p><p><strong>в)</strong></p><p>На графике (рис. в) изображен ток в виде последовательности однополярных прямоугольных импульсов. В течение одного периода $T$ ток равен $I_0$ на интервале времени от $0$ до $\tau$ и равен нулю на остальной части периода, от $\tau$ до $T$.</p><p>Найдем среднее значение квадрата силы тока за период $T$:</p><p>$I^2 = \frac{1}{T} \int_0^T i(t)^2 \, dt = \frac{1}{T} \left( \int_0^\tau (I_0)^2 \, dt + \int_\tau^T (0)^2 \, dt \right)$</p><p>Второй интеграл равен нулю. Вычисляем первый:</p><p>$I^2 = \frac{1}{T} \int_0^\tau I_0^2 \, dt = \frac{I_0^2}{T} [t]_0^\tau = \frac{I_0^2}{T} (\tau - 0) = \frac{I_0^2 \tau}{T}$</p><p>Отсюда находим действующее значение тока:</p><p>$I = \sqrt{\frac{I_0^2 \tau}{T}} = I_0 \sqrt{\frac{\tau}{T}}$</p><p><strong>Ответ:</strong> $I = I_0 \sqrt{\frac{\tau}{T}}$.</p>"
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            "id" => 1691492
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            "task" => array:2 [
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              "type" => "task"
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            "text" => "<p><strong>Дано:</strong></p><p>Графики зависимости мгновенной силы тока $i$ от времени $t$ для трех случаев (рис. а, б, в).</p><p>Амплитудное значение тока: $I_0$.</p><p>Период тока: $T$.</p><p>Длительность импульса для случая в: $\tau$.</p><p><strong>Найти:</strong></p><p>Действующее значение переменного тока $I$ для каждого случая.</p><p><strong>Решение:</strong></p><p>Действующее (или эффективное) значение переменного тока $I$ определяется как значение такого постоянного тока, который за время, равное периоду переменного тока, выделит в проводнике то же количество теплоты, что и данный переменный ток. Квадрат действующего значения $I^2$ равен среднему значению квадрата мгновенной силы тока $i^2$ за период $T$. Это значение вычисляется по формуле:</p><p>$I^2 = \overline{i^2} = \frac{1}{T} \int_0^T i(t)^2 \, dt$</p><p>Соответственно, действующее значение тока равно $I = \sqrt{\overline{i^2}}$.</p><p>Рассчитаем действующее значение тока для каждого из трех представленных случаев.</p><p><strong>а)</strong></p><p>На графике (рис. а) изображен переменный ток прямоугольной формы (меандр). В течение первой половины периода ($0 \le t &lt; T/2$) сила тока равна $I_0$, а в течение второй половины ($T/2 \le t &lt; T$) — $-I_0$.</p><p>Квадрат мгновенного значения силы тока $i^2$ остается постоянным в течение всего периода:</p><p>Если $i = I_0$, то $i^2 = I_0^2$.</p><p>Если $i = -I_0$, то $i^2 = (-I_0)^2 = I_0^2$.</p><p>Таким образом, среднее значение квадрата силы тока за период равно самому этому значению:</p><p>$I^2 = \overline{i^2} = I_0^2$</p><p>Отсюда находим действующее значение тока:</p><p>$I = \sqrt{I_0^2} = I_0$</p><p><strong>Ответ:</strong> $I = I_0$.</p><p><strong>б)</strong></p><p>На графике (рис. б) изображен ток в виде последовательности разнополярных импульсов. Согласно приведенной в задании формуле для решения, будем считать, что за один период $T$ ток принимает значение $I_0$ в течение общего времени $T/8$, значение $-I_0$ в течение общего времени $T/8$, а в остальное время он равен нулю.</p><p>Найдем среднее значение квадрата силы тока за период $T$, используя определение:</p><p>$I^2 = \frac{1}{T} \int_0^T i(t)^2 \, dt$</p><p>Поскольку ток отличен от нуля только в определенные промежутки времени, интеграл можно разбить на части. Общее количество тепла за период $T$ пропорционально $I^2T$. Это же количество тепла выделяется переменным током:</p><p>$I^2 T = I_0^2 \cdot \frac{T}{8} + (-I_0)^2 \cdot \frac{T}{8}$</p><p>Упростим выражение:</p><p>$I^2 T = I_0^2 \frac{T}{8} + I_0^2 \frac{T}{8} = I_0^2 \frac{2T}{8} = I_0^2 \frac{T}{4}$</p><p>Сократив на $T$, получим:</p><p>$I^2 = \frac{I_0^2}{4}$</p><p>Действующее значение тока равно:</p><p>$I = \sqrt{\frac{I_0^2}{4}} = \frac{I_0}{2}$</p><p><strong>Ответ:</strong> $I = I_0/2$.</p><p><strong>в)</strong></p><p>На графике (рис. в) изображен ток в виде последовательности однополярных прямоугольных импульсов. В течение одного периода $T$ ток равен $I_0$ на интервале времени от $0$ до $\tau$ и равен нулю на остальной части периода, от $\tau$ до $T$.</p><p>Найдем среднее значение квадрата силы тока за период $T$:</p><p>$I^2 = \frac{1}{T} \int_0^T i(t)^2 \, dt = \frac{1}{T} \left( \int_0^\tau (I_0)^2 \, dt + \int_\tau^T (0)^2 \, dt \right)$</p><p>Второй интеграл равен нулю. Вычисляем первый:</p><p>$I^2 = \frac{1}{T} \int_0^\tau I_0^2 \, dt = \frac{I_0^2}{T} [t]_0^\tau = \frac{I_0^2}{T} (\tau - 0) = \frac{I_0^2 \tau}{T}$</p><p>Отсюда находим действующее значение тока:</p><p>$I = \sqrt{\frac{I_0^2 \tau}{T}} = I_0 \sqrt{\frac{\tau}{T}}$</p><p><strong>Ответ:</strong> $I = I_0 \sqrt{\frac{\tau}{T}}$.</p>"
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                        0 => App\Models\Element {#1247
                          #connection: "mysql"
                          #table: "elements"
                          #primaryKey: "id"
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                            "id" => 1493934
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "edition" => Illuminate\Database\Eloquent\Collection {#1248
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                            "text" => "<p><strong>33.3.</strong> На рисунках приведены графики изменений напряжения на конденсаторе колебательного контура и силы тока в катушке этого контура. Найдите емкость конденсатора и индуктивность катушки контура.</p><p>☑ 13000 пФ; 7,6 мкГн.</p><p><strong>Решение.</strong> Из приведенных в условии графиков видно, что период колебаний $T = 2$ мкс, амплитудные значения напряжения и силы тока $U_m = 12$ В, $I_m = 0,5$ А. Согласно закону сохранения энергии $C U_m^2 / 2 = L I_m^2 / 2$. Используя также формулу Томсона $T = 2\pi\sqrt{LC}$, получим окончательно: но: $C = \frac{T \cdot I_m}{2\pi U_m}$, $L = \frac{T \cdot U_m}{2\pi I_m}$.</p>"
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                                "alt" => null
                                "width" => "1383"
                                "height" => 197
                                "path" => "/media/fizika_10/gelfgat-z/0-33/3-1.webp?ts=1756251143"
                              ]
                              1 => array:5 [
                                "name" => "3-2.jpg"
                                "alt" => null
                                "width" => "1398"
                                "height" => 1125
                                "path" => "/media/fizika_10/gelfgat-z/0-33/3-2.webp?ts=1756251143"
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                            "id" => 1493934
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "edition" => Illuminate\Database\Eloquent\Collection {#1248}
                            "task" => array:2 [
                              "refs" => "1319783"
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                            "text" => "<p><strong>33.3.</strong> На рисунках приведены графики изменений напряжения на конденсаторе колебательного контура и силы тока в катушке этого контура. Найдите емкость конденсатора и индуктивность катушки контура.</p><p>☑ 13000 пФ; 7,6 мкГн.</p><p><strong>Решение.</strong> Из приведенных в условии графиков видно, что период колебаний $T = 2$ мкс, амплитудные значения напряжения и силы тока $U_m = 12$ В, $I_m = 0,5$ А. Согласно закону сохранения энергии $C U_m^2 / 2 = L I_m^2 / 2$. Используя также формулу Томсона $T = 2\pi\sqrt{LC}$, получим окончательно: но: $C = \frac{T \cdot I_m}{2\pi U_m}$, $L = \frac{T \cdot U_m}{2\pi I_m}$.</p>"
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                        1 => App\Models\Element {#1249
                          #connection: "mysql"
                          #table: "elements"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: true
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                            "created_at" => "2026-04-10 13:58:26"
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                            "text" => "<p><strong>Дано:</strong></p><p>На основе предоставленных графиков определим параметры колебательного контура:</p><p>Амплитудное значение напряжения на конденсаторе: $U_m = 12$ В.</p><p>Амплитудное значение силы тока в катушке: $I_m = 0,5$ А.</p><p>Период колебаний (время одного полного цикла): $T = 2$ мкс.</p><p>Перевод в систему СИ:</p><p>$T = 2 \text{ мкс} = 2 \cdot 10^{-6}$ с.</p><p><strong>Найти:</strong></p><p>Емкость конденсатора $C$ — ?</p><p>Индуктивность катушки $L$ — ?</p><p><strong>Решение:</strong></p><p>В идеальном колебательном контуре (без потерь энергии) полная электромагнитная энергия сохраняется. Энергия периодически переходит из электрического поля конденсатора в магнитное поле катушки и обратно. Максимальная энергия электрического поля конденсатора равна максимальной энергии магнитного поля катушки:</p><p>$W_{C,max} = W_{L,max}$</p><p>Подставим формулы для максимальной энергии:</p><p>$\frac{C U_m^2}{2} = \frac{L I_m^2}{2}$</p><p>Из этого закона сохранения энергии мы получаем первое соотношение между искомыми величинами $C$ и $L$:</p><p>$C U_m^2 = L I_m^2$ (1)</p><p>Вторым уравнением, связывающим параметры контура, является формула Томсона для периода свободных электромагнитных колебаний:</p><p>$T = 2\pi\sqrt{LC}$ (2)</p><p>Таким образом, мы имеем систему из двух уравнений с двумя неизвестными. Решим эту систему.</p><p>Из уравнения (1) выразим индуктивность $L$ через емкость $C$:</p><p>$L = C \frac{U_m^2}{I_m^2}$</p><p>Подставим это выражение для $L$ в формулу Томсона (2):</p><p>$T = 2\pi\sqrt{\left(C \frac{U_m^2}{I_m^2}\right)C} = 2\pi\sqrt{C^2 \frac{U_m^2}{I_m^2}} = 2\pi C \frac{U_m}{I_m}$</p><p>Из полученного соотношения выразим емкость конденсатора $C$:</p><p>$C = \frac{T \cdot I_m}{2\pi U_m}$</p><p>Подставим числовые значения из условия:</p><p>$C = \frac{2 \cdot 10^{-6} \text{ с} \cdot 0,5 \text{ А}}{2\pi \cdot 12 \text{ В}} = \frac{1 \cdot 10^{-6}}{24\pi} \text{ Ф} \approx 0,01326 \cdot 10^{-6} \text{ Ф}$</p><p>Переведем в пикофарады ($1 \text{ пФ} = 10^{-12} \text{ Ф}$):</p><p>$C \approx 13260 \cdot 10^{-12} \text{ Ф} = 13260$ пФ.</p><p>Округляя до двух значащих цифр, получаем $C \approx 13000$ пФ.</p><p>Теперь найдем индуктивность катушки $L$. Из соотношения (1) выразим емкость $C$ через индуктивность $L$:</p><p>$C = L \frac{I_m^2}{U_m^2}$</p><p>Подставим это выражение в формулу Томсона (2):</p><p>$T = 2\pi\sqrt{L \left(L \frac{I_m^2}{U_m^2}\right)} = 2\pi\sqrt{L^2 \frac{I_m^2}{U_m^2}} = 2\pi L \frac{I_m}{U_m}$</p><p>Выразим индуктивность $L$:</p><p>$L = \frac{T \cdot U_m}{2\pi I_m}$</p><p>Подставим числовые значения:</p><p>$L = \frac{2 \cdot 10^{-6} \text{ с} \cdot 12 \text{ В}}{2\pi \cdot 0,5 \text{ А}} = \frac{24 \cdot 10^{-6}}{\pi} \text{ Гн} \approx 7,639 \cdot 10^{-6} \text{ Гн}$</p><p>Переведем в микрогенри ($1 \text{ мкГн} = 10^{-6} \text{ Гн}$):</p><p>$L \approx 7,639$ мкГн.</p><p>Округляя до двух значащих цифр, получаем $L \approx 7,6$ мкГн.</p><p><strong>Ответ:</strong> емкость конденсатора $C \approx 13000$ пФ; индуктивность катушки $L \approx 7,6$ мкГн.</p>"
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                            "task" => array:2 [
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                              "type" => "task"
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                            "text" => "<p><strong>Дано:</strong></p><p>На основе предоставленных графиков определим параметры колебательного контура:</p><p>Амплитудное значение напряжения на конденсаторе: $U_m = 12$ В.</p><p>Амплитудное значение силы тока в катушке: $I_m = 0,5$ А.</p><p>Период колебаний (время одного полного цикла): $T = 2$ мкс.</p><p>Перевод в систему СИ:</p><p>$T = 2 \text{ мкс} = 2 \cdot 10^{-6}$ с.</p><p><strong>Найти:</strong></p><p>Емкость конденсатора $C$ — ?</p><p>Индуктивность катушки $L$ — ?</p><p><strong>Решение:</strong></p><p>В идеальном колебательном контуре (без потерь энергии) полная электромагнитная энергия сохраняется. Энергия периодически переходит из электрического поля конденсатора в магнитное поле катушки и обратно. Максимальная энергия электрического поля конденсатора равна максимальной энергии магнитного поля катушки:</p><p>$W_{C,max} = W_{L,max}$</p><p>Подставим формулы для максимальной энергии:</p><p>$\frac{C U_m^2}{2} = \frac{L I_m^2}{2}$</p><p>Из этого закона сохранения энергии мы получаем первое соотношение между искомыми величинами $C$ и $L$:</p><p>$C U_m^2 = L I_m^2$ (1)</p><p>Вторым уравнением, связывающим параметры контура, является формула Томсона для периода свободных электромагнитных колебаний:</p><p>$T = 2\pi\sqrt{LC}$ (2)</p><p>Таким образом, мы имеем систему из двух уравнений с двумя неизвестными. Решим эту систему.</p><p>Из уравнения (1) выразим индуктивность $L$ через емкость $C$:</p><p>$L = C \frac{U_m^2}{I_m^2}$</p><p>Подставим это выражение для $L$ в формулу Томсона (2):</p><p>$T = 2\pi\sqrt{\left(C \frac{U_m^2}{I_m^2}\right)C} = 2\pi\sqrt{C^2 \frac{U_m^2}{I_m^2}} = 2\pi C \frac{U_m}{I_m}$</p><p>Из полученного соотношения выразим емкость конденсатора $C$:</p><p>$C = \frac{T \cdot I_m}{2\pi U_m}$</p><p>Подставим числовые значения из условия:</p><p>$C = \frac{2 \cdot 10^{-6} \text{ с} \cdot 0,5 \text{ А}}{2\pi \cdot 12 \text{ В}} = \frac{1 \cdot 10^{-6}}{24\pi} \text{ Ф} \approx 0,01326 \cdot 10^{-6} \text{ Ф}$</p><p>Переведем в пикофарады ($1 \text{ пФ} = 10^{-12} \text{ Ф}$):</p><p>$C \approx 13260 \cdot 10^{-12} \text{ Ф} = 13260$ пФ.</p><p>Округляя до двух значащих цифр, получаем $C \approx 13000$ пФ.</p><p>Теперь найдем индуктивность катушки $L$. Из соотношения (1) выразим емкость $C$ через индуктивность $L$:</p><p>$C = L \frac{I_m^2}{U_m^2}$</p><p>Подставим это выражение в формулу Томсона (2):</p><p>$T = 2\pi\sqrt{L \left(L \frac{I_m^2}{U_m^2}\right)} = 2\pi\sqrt{L^2 \frac{I_m^2}{U_m^2}} = 2\pi L \frac{I_m}{U_m}$</p><p>Выразим индуктивность $L$:</p><p>$L = \frac{T \cdot U_m}{2\pi I_m}$</p><p>Подставим числовые значения:</p><p>$L = \frac{2 \cdot 10^{-6} \text{ с} \cdot 12 \text{ В}}{2\pi \cdot 0,5 \text{ А}} = \frac{24 \cdot 10^{-6}}{\pi} \text{ Гн} \approx 7,639 \cdot 10^{-6} \text{ Гн}$</p><p>Переведем в микрогенри ($1 \text{ мкГн} = 10^{-6} \text{ Гн}$):</p><p>$L \approx 7,639$ мкГн.</p><p>Округляя до двух значащих цифр, получаем $L \approx 7,6$ мкГн.</p><p><strong>Ответ:</strong> емкость конденсатора $C \approx 13000$ пФ; индуктивность катушки $L \approx 7,6$ мкГн.</p>"
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№33.4 (с. 242)
Условие. №33.4 (с. 242)
скриншот условия
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 242, номер 33.4, Условие

33.4. Найдите действующее значение $\text{I}$ переменного тока (см. рис. а, б, в).

Решение. Величина $\text{I}$ представляет собой значение силы постоянного тока, при прохождении которого в проводнике выделяется такое же количество теплоты, как и при прохождении данного переменного тока за это же время (т. е. $I^2 = \overline{i^2}$).

а) Квадрат силы тока в любой момент равен $I_0^2$. Поэтому $I = I_0$.

б) $I^2 T = I_0^2 \cdot \frac{T}{8} + (-I_0)^2 \cdot \frac{T}{8}$, откуда $I = I_0/2$.

в) $I^2 T = I_0^2 \tau$, откуда $I = I_0 \sqrt{\frac{\tau}{T}}$.

Решение. №33.4 (с. 242)

Дано:

Графики зависимости мгновенной силы тока $i$ от времени $t$ для трех случаев (рис. а, б, в).

Амплитудное значение тока: $I_0$.

Период тока: $T$.

Длительность импульса для случая в: $\tau$.

Найти:

Действующее значение переменного тока $I$ для каждого случая.

Решение:

Действующее (или эффективное) значение переменного тока $I$ определяется как значение такого постоянного тока, который за время, равное периоду переменного тока, выделит в проводнике то же количество теплоты, что и данный переменный ток. Квадрат действующего значения $I^2$ равен среднему значению квадрата мгновенной силы тока $i^2$ за период $T$. Это значение вычисляется по формуле:

$I^2 = \overline{i^2} = \frac{1}{T} \int_0^T i(t)^2 \, dt$

Соответственно, действующее значение тока равно $I = \sqrt{\overline{i^2}}$.

Рассчитаем действующее значение тока для каждого из трех представленных случаев.

а)

На графике (рис. а) изображен переменный ток прямоугольной формы (меандр). В течение первой половины периода ($0 \le t < T/2$) сила тока равна $I_0$, а в течение второй половины ($T/2 \le t < T$) — $-I_0$.

Квадрат мгновенного значения силы тока $i^2$ остается постоянным в течение всего периода:

Если $i = I_0$, то $i^2 = I_0^2$.

Если $i = -I_0$, то $i^2 = (-I_0)^2 = I_0^2$.

Таким образом, среднее значение квадрата силы тока за период равно самому этому значению:

$I^2 = \overline{i^2} = I_0^2$

Отсюда находим действующее значение тока:

$I = \sqrt{I_0^2} = I_0$

Ответ: $I = I_0$.

б)

На графике (рис. б) изображен ток в виде последовательности разнополярных импульсов. Согласно приведенной в задании формуле для решения, будем считать, что за один период $T$ ток принимает значение $I_0$ в течение общего времени $T/8$, значение $-I_0$ в течение общего времени $T/8$, а в остальное время он равен нулю.

Найдем среднее значение квадрата силы тока за период $T$, используя определение:

$I^2 = \frac{1}{T} \int_0^T i(t)^2 \, dt$

Поскольку ток отличен от нуля только в определенные промежутки времени, интеграл можно разбить на части. Общее количество тепла за период $T$ пропорционально $I^2T$. Это же количество тепла выделяется переменным током:

$I^2 T = I_0^2 \cdot \frac{T}{8} + (-I_0)^2 \cdot \frac{T}{8}$

Упростим выражение:

$I^2 T = I_0^2 \frac{T}{8} + I_0^2 \frac{T}{8} = I_0^2 \frac{2T}{8} = I_0^2 \frac{T}{4}$

Сократив на $T$, получим:

$I^2 = \frac{I_0^2}{4}$

Действующее значение тока равно:

$I = \sqrt{\frac{I_0^2}{4}} = \frac{I_0}{2}$

Ответ: $I = I_0/2$.

в)

На графике (рис. в) изображен ток в виде последовательности однополярных прямоугольных импульсов. В течение одного периода $T$ ток равен $I_0$ на интервале времени от $0$ до $\tau$ и равен нулю на остальной части периода, от $\tau$ до $T$.

Найдем среднее значение квадрата силы тока за период $T$:

$I^2 = \frac{1}{T} \int_0^T i(t)^2 \, dt = \frac{1}{T} \left( \int_0^\tau (I_0)^2 \, dt + \int_\tau^T (0)^2 \, dt \right)$

Второй интеграл равен нулю. Вычисляем первый:

$I^2 = \frac{1}{T} \int_0^\tau I_0^2 \, dt = \frac{I_0^2}{T} [t]_0^\tau = \frac{I_0^2}{T} (\tau - 0) = \frac{I_0^2 \tau}{T}$

Отсюда находим действующее значение тока:

$I = \sqrt{\frac{I_0^2 \tau}{T}} = I_0 \sqrt{\frac{\tau}{T}}$

Ответ: $I = I_0 \sqrt{\frac{\tau}{T}}$.

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