Номер 2, страница 123 - гдз по физике 9 класс учебник Изергин

Физика, 9 класс Учебник, автор: Изергин Эдуард Тимофеевич, издательство Русское слово, Москва, 2019

Авторы: Изергин Э. Т.

Тип: Учебник

Серия: инновационная школа

Издательство: Русское слово

Год издания: 2019 - 2026

Цвет обложки: синий

ISBN: 978-5-533-01069-6

Глава IV. Электромагнитные колебания и волны. Параграф 24. Электромагнитные колебания - номер 2, страница 123.

App\Models\Task {#1024 // resources/views/models/task/default.blade.php
  #connection: "mysql"
  #table: "tasks"
  #primaryKey: "id"
  #keyType: "int"
  +incrementing: true
  #with: []
  #withCount: []
  +preventsLazyLoading: false
  #perPage: 15
  +exists: true
  +wasRecentlyCreated: false
  #escapeWhenCastingToString: false
  #attributes: array:24 [
    "id" => 1439816
    "created_at" => "2026-04-10 13:58:26"
    "updated_at" => null
    "field_page_start" => "123"
    "field_page_end" => null
    "field_url" => "/9-klass/fizika/izergin-uchebnik/24-2"
    "field_display_title" => "2"
    "field_outside_task" => null
    "field_task_type" => Illuminate\Database\Eloquent\Collection {#331
      #items: array:1 [
        0 => App\Models\Term {#1029
          #connection: "mysql"
          #table: "terms"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: false
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          #attributes: array:6 [
            "id" => 26
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
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            "field_cases" => array:6 [
              "field_accusative_case" => "номер"
              "field_creative_case" => "номером"
              "field_dative_case" => "номеру"
              "field_genitive_case" => "номера"
              "field_nominative_case" => "номер"
              "field_prepositional_case" => "номере"
            ]
            "field_short_name" => ""
          ]
          #original: array:6 [
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            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
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            "field_cases" => array:6 [
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              "field_nominative_case" => "номер"
              "field_prepositional_case" => "номере"
            ]
            "field_short_name" => ""
          ]
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            0 => "*"
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      #escapeWhenCastingToString: false
    }
    "field_metatags_title" => null
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    "field_h1" => null
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    "field_description_bottom" => null
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    "breadcrumbs" => []
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      #items: []
      #escapeWhenCastingToString: false
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        0 => App\Models\Branch {#1023
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          #table: "branches"
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            "id" => 1439571
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
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            "field_branch_order" => "IV"
            "field_url" => null
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                      "field_prepositional_case" => "Главе"
                    ]
                    "field_page_check_not_needed" => null
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                  ]
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              #items: array:1 [
                0 => App\Models\Book {#1032
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                  #attributes: array:50 [
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                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
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                    "field_subject" => Illuminate\Database\Eloquent\Collection {#1034
                      #items: array:1 [
                        0 => App\Models\Term {#1035
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
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                            "id" => 6493
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
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                            "field_cases" => array:6 [
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                          ]
                          #original: array:10 [
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                            "updated_at" => null
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                              "field_prepositional_case" => "физике"
                            ]
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                            "field_subject_type" => "technical_subject"
                            "field_translit" => "fizika"
                          ]
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                    "field_class" => Illuminate\Database\Eloquent\Collection {#1036
                      #items: array:1 [
                        0 => App\Models\Term {#1037
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
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                          #attributes: array:6 [
                            "id" => 5458
                            "created_at" => "2026-04-10 13:58:26"
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                              "field_genitive_case" => "девятого"
                              "field_nominative_case" => "девятый"
                              "field_prepositional_case" => "девятом"
                            ]
                            "field_translit" => "devjatyj"
                          ]
                          #original: array:6 [
                            "id" => 5458
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "9"
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                              "field_prepositional_case" => "девятом"
                            ]
                            "field_translit" => "devjatyj"
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                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1038
                      #items: array:1 [
                        0 => App\Models\Term {#1039
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                          #table: "terms"
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                            "created_at" => "2026-04-10 13:58:26"
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                      #items: array:1 [
                        0 => App\Models\Term {#1041
                          #connection: "mysql"
                          #table: "terms"
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                            "field_foreign_lang_patronymic" => null
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                          ]
                          #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 {#1049
                      #items: array:1 [
                        0 => App\Models\Term {#1050
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:8 [
                            "id" => 4715
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "инновационная школа"
                            "field_cases" => null
                            "field_foreign_lang_series" => null
                            "field_transcription_eng" => null
                            "field_translit" => "innovacionnaya shkola"
                          ]
                          #original: array:8 [
                            "id" => 4715
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "инновационная школа"
                            "field_cases" => null
                            "field_foreign_lang_series" => null
                            "field_transcription_eng" => null
                            "field_translit" => "innovacionnaya shkola"
                          ]
                          #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_umk" => Illuminate\Database\Eloquent\Collection {#1051
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1052
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1053
                      #items: array:1 [
                        0 => App\Models\Term {#1054
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:10 [
                            "id" => 6706
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "ФГОС (старый)"
                            "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_color" => null
                            "field_end_year" => "2022"
                            "field_start_year" => "2019"
                            "field_translit" => "fgos-old"
                            "field_type" => null
                          ]
                          #original: array:10 [
                            "id" => 6706
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "ФГОС (старый)"
                            "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_color" => null
                            "field_end_year" => "2022"
                            "field_start_year" => "2019"
                            "field_translit" => "fgos-old"
                            "field_type" => null
                          ]
                          #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_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1055
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1056
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => null
                    "field_publication_year" => "2019"
                    "field_publication_year_until" => null
                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебник для 9 класса общеобразовательных организаций"
                    "field_allowed" => null
                    "field_reserve_field" => null
                    "field_link_to_source" => null
                    "field_tasks_count" => "388"
                    "field_priority" => null
                    "field_default_folder" => "/fizika_09/izergin-u/"
                    "field_isbn" => "978-5-533-01069-6"
                    "field_cover" => array:1 [
                      0 => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                        "alt" => ""
                        "width" => "1881"
                        "height" => "2502"
                      ]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1057
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1058
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1059
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_url" => "/9-klass/fizika/izergin-uchebnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1060
                      #items: array:1 [
                        0 => App\Models\Term {#1061
                          #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" => 49
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "синий"
                            "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" => "siniy"
                          ]
                          #original: array:6 [
                            "id" => 49
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "синий"
                            "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" => "siniy"
                          ]
                          #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" => 380
                      "subject" => 556
                      "class_subject" => 493
                    ]
                  ]
                  #original: array:50 [
                    "id" => 4169
                    "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 {#1034}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1036}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1038}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1040}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1042}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1043}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1045}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1047}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1049}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1051}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1052}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1053}
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1055}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1056}
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => null
                    "field_publication_year" => "2019"
                    "field_publication_year_until" => null
                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебник для 9 класса общеобразовательных организаций"
                    "field_allowed" => null
                    "field_reserve_field" => null
                    "field_link_to_source" => null
                    "field_tasks_count" => "388"
                    "field_priority" => null
                    "field_default_folder" => "/fizika_09/izergin-u/"
                    "field_isbn" => "978-5-533-01069-6"
                    "field_cover" => array:1 [
                      0 => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                        "alt" => ""
                        "width" => "1881"
                        "height" => "2502"
                      ]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1057}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1058}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1059}
                    "field_url" => "/9-klass/fizika/izergin-uchebnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1060}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "breadcrumbs" => array:3 [
                      "class" => 380
                      "subject" => 556
                      "class_subject" => 493
                    ]
                  ]
                  #changes: []
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                  #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 {#1062
              #items: []
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1439571
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Электромагнитные колебания и волны"
            "field_branch_order" => "IV"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#333}
            "field_page_start" => "115"
            "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 {#1030}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1062}
          ]
          #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 {#1063
      #items: array:2 [
        0 => App\Models\Branch {#1023}
        1 => App\Models\Branch {#1064
          #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" => 1439573
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Электромагнитные колебания"
            "field_branch_order" => "24"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1065
              #items: array:1 [
                0 => App\Models\Term {#1066
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:7 [
                    "id" => 32
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Параграф"
                    "field_cases" => array:6 [
                      "field_accusative_case" => "Параграф"
                      "field_creative_case" => "Параграфом"
                      "field_dative_case" => "Параграфу"
                      "field_genitive_case" => "Параграфа"
                      "field_nominative_case" => "Параграф"
                      "field_prepositional_case" => "Параграфе"
                    ]
                    "field_page_check_not_needed" => null
                    "field_short_name" => "§"
                  ]
                  #original: array:7 [
                    "id" => 32
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Параграф"
                    "field_cases" => array:6 [
                      "field_accusative_case" => "Параграф"
                      "field_creative_case" => "Параграфом"
                      "field_dative_case" => "Параграфу"
                      "field_genitive_case" => "Параграфа"
                      "field_nominative_case" => "Параграф"
                      "field_prepositional_case" => "Параграфе"
                    ]
                    "field_page_check_not_needed" => null
                    "field_short_name" => "§"
                  ]
                  #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_page_start" => "118"
            "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 {#1067
              #items: array:1 [
                0 => App\Models\Book {#1032}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1068
              #items: array:1 [
                0 => App\Models\Branch {#1069
                  #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" => 1439571
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Электромагнитные колебания и волны"
                    "field_branch_order" => "IV"
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1070
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "115"
                    "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 {#1071
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1072
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                  ]
                  #original: array:24 [
                    "id" => 1439571
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Электромагнитные колебания и волны"
                    "field_branch_order" => "IV"
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1070}
                    "field_page_start" => "115"
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                    "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
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                    "field_branch_covers" => []
                    "book" => Illuminate\Database\Eloquent\Collection {#1071}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1072}
                  ]
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #dispatchesEvents: []
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                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1439573
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Электромагнитные колебания"
            "field_branch_order" => "24"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1065}
            "field_page_start" => "118"
            "field_branch_display" => "0"
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            "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
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            "text" => "<p><strong>2.</strong> Колебательный контур — это простейшая электрическая цепь, состоящая из соединенных между собой катушки индуктивности (элемента, обладающего индуктивностью $\text{L}$) и конденсатора (элемента, обладающего ёмкостью $\text{C}$). В такой системе могут возникать и поддерживаться свободные электромагнитные колебания.</p><p>Рассмотрим процесс колебаний в идеальном колебательном контуре, то есть в контуре, активное сопротивление которого пренебрежимо мало ($R \approx 0$).</p><ol><li><p>Пусть в начальный момент времени конденсатор заряжен до максимального напряжения $U_{max}$, а ток в цепи отсутствует. Вся энергия системы сосредоточена в электрическом поле конденсатора и равна $W_Э = \frac{C U_{max}^2}{2}$.</p></li><li><p>Конденсатор начинает разряжаться через катушку индуктивности. В цепи возникает электрический ток, сила которого постепенно нарастает. Нарастающий ток создает в катушке переменное магнитное поле. Энергия электрического поля конденсатора начинает переходить в энергию магнитного поля катушки ($W_М = \frac{L I^2}{2}$).</p></li><li><p>В момент, когда конденсатор полностью разрядится (напряжение на его обкладках станет равным нулю), сила тока в катушке достигнет своего максимального значения $I_{max}$. В этот момент вся энергия контура будет сосредоточена в магнитном поле катушки: $W_М = \frac{L I_{max}^2}{2}$.</p></li><li><p>Несмотря на то, что конденсатор разрядился, ток в цепи не исчезает мгновенно из-за явления самоиндукции. Катушка индуктивности "препятствует" исчезновению тока, и он продолжает течь в том же направлении, перезаряжая конденсатор. Теперь обкладка, которая была заряжена положительно, становится отрицательной, и наоборот.</p></li><li><p>Ток постепенно уменьшается до нуля. К моменту его полного исчезновения конденсатор окажется полностью перезаряженным, а напряжение на нем достигнет максимального значения, но с противоположным знаком ($-U_{max}$). Энергия магнитного поля катушки полностью перейдет обратно в энергию электрического поля конденсатора.</p></li><li><p>Далее процесс повторяется в обратном направлении. Конденсатор снова начинает разряжаться, и в цепи возникает ток противоположного направления. Так происходят периодические превращения энергии электрического поля в энергию магнитного поля и обратно — электромагнитные колебания.</p></li></ol><p>Период этих свободных колебаний в идеальном контуре определяется <strong>формулой Томсона</strong>:</p><p>$T = 2\pi\sqrt{LC}$</p><p>В реальном колебательном контуре всегда есть активное сопротивление, на котором происходит потеря энергии (выделение тепла). Поэтому свободные колебания в реальном контуре являются затухающими.</p><p><strong>Ответ:</strong> Колебательный контур — это электрическая цепь, состоящая из катушки индуктивности и конденсатора, в которой могут происходить свободные электромагнитные колебания за счёт периодического превращения энергии электрического поля конденсатора в энергию магнитного поля катушки и обратно.</p>"
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            "text" => "<p><strong>2.</strong> Колебательный контур — это простейшая электрическая цепь, состоящая из соединенных между собой катушки индуктивности (элемента, обладающего индуктивностью $\text{L}$) и конденсатора (элемента, обладающего ёмкостью $\text{C}$). В такой системе могут возникать и поддерживаться свободные электромагнитные колебания.</p><p>Рассмотрим процесс колебаний в идеальном колебательном контуре, то есть в контуре, активное сопротивление которого пренебрежимо мало ($R \approx 0$).</p><ol><li><p>Пусть в начальный момент времени конденсатор заряжен до максимального напряжения $U_{max}$, а ток в цепи отсутствует. Вся энергия системы сосредоточена в электрическом поле конденсатора и равна $W_Э = \frac{C U_{max}^2}{2}$.</p></li><li><p>Конденсатор начинает разряжаться через катушку индуктивности. В цепи возникает электрический ток, сила которого постепенно нарастает. Нарастающий ток создает в катушке переменное магнитное поле. Энергия электрического поля конденсатора начинает переходить в энергию магнитного поля катушки ($W_М = \frac{L I^2}{2}$).</p></li><li><p>В момент, когда конденсатор полностью разрядится (напряжение на его обкладках станет равным нулю), сила тока в катушке достигнет своего максимального значения $I_{max}$. В этот момент вся энергия контура будет сосредоточена в магнитном поле катушки: $W_М = \frac{L I_{max}^2}{2}$.</p></li><li><p>Несмотря на то, что конденсатор разрядился, ток в цепи не исчезает мгновенно из-за явления самоиндукции. Катушка индуктивности "препятствует" исчезновению тока, и он продолжает течь в том же направлении, перезаряжая конденсатор. Теперь обкладка, которая была заряжена положительно, становится отрицательной, и наоборот.</p></li><li><p>Ток постепенно уменьшается до нуля. К моменту его полного исчезновения конденсатор окажется полностью перезаряженным, а напряжение на нем достигнет максимального значения, но с противоположным знаком ($-U_{max}$). Энергия магнитного поля катушки полностью перейдет обратно в энергию электрического поля конденсатора.</p></li><li><p>Далее процесс повторяется в обратном направлении. Конденсатор снова начинает разряжаться, и в цепи возникает ток противоположного направления. Так происходят периодические превращения энергии электрического поля в энергию магнитного поля и обратно — электромагнитные колебания.</p></li></ol><p>Период этих свободных колебаний в идеальном контуре определяется <strong>формулой Томсона</strong>:</p><p>$T = 2\pi\sqrt{LC}$</p><p>В реальном колебательном контуре всегда есть активное сопротивление, на котором происходит потеря энергии (выделение тепла). Поэтому свободные колебания в реальном контуре являются затухающими.</p><p><strong>Ответ:</strong> Колебательный контур — это электрическая цепь, состоящая из катушки индуктивности и конденсатора, в которой могут происходить свободные электромагнитные колебания за счёт периодического превращения энергии электрического поля конденсатора в энергию магнитного поля катушки и обратно.</p>"
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                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1129
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                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1130
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => null
                    "field_publication_year" => "2019"
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                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебник для 9 класса общеобразовательных организаций"
                    "field_allowed" => null
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                    "field_link_to_source" => null
                    "field_tasks_count" => "388"
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                    "field_default_folder" => "/fizika_09/izergin-u/"
                    "field_isbn" => "978-5-533-01069-6"
                    "field_cover" => array:1 [
                      0 => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [ …4]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1131
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                      #escapeWhenCastingToString: false
                    }
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                    }
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                    }
                    "field_url" => "/9-klass/fizika/izergin-uchebnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1134
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                      #escapeWhenCastingToString: false
                    }
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                    "field_publication_number" => null
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                    "field_default_folder" => "/fizika_09/izergin-u/"
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                    "field_cover" => array:1 [
                      0 => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [ …4]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1131}
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                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1133}
                    "field_url" => "/9-klass/fizika/izergin-uchebnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1134}
                    "field_metatags_title" => null
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                    ]
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                  #touches: []
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                  #visible: []
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                    0 => "*"
                  ]
                }
              ]
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            "field_metatags_title" => null
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            }
            "content" => Illuminate\Database\Eloquent\Collection {#1147
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                0 => App\Models\Element {#1146
                  #connection: "mysql"
                  #table: "elements"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
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                  #withCount: []
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                  #attributes: array:6 [
                    "id" => 1707679
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "edition" => Illuminate\Database\Eloquent\Collection {#1156
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                    "book_page" => array:2 [
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                      "type" => "book_page"
                    ]
                    "img" => array:1 [
                      0 => array:5 [ …5]
                    ]
                  ]
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                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "edition" => Illuminate\Database\Eloquent\Collection {#1156}
                    "book_page" => array:2 [
                      "refs" => "1439441"
                      "type" => "book_page"
                    ]
                    "img" => array:1 [
                      0 => array:5 [ …5]
                    ]
                  ]
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                    0 => "*"
                  ]
                }
              ]
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            }
            "next" => array:2 [
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            "previous" => array:2 [
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              "type" => "book_page"
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            "tasks" => Illuminate\Database\Eloquent\Collection {#1551
              #items: array:7 [
                0 => App\Models\Task {#1565
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
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                  #perPage: 15
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                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
                    "id" => 1439815
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_page_start" => "123"
                    "field_page_end" => null
                    "field_url" => "/9-klass/fizika/izergin-uchebnik/24-1"
                    "field_display_title" => "1"
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                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1569
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                      #escapeWhenCastingToString: false
                    }
                    "field_metatags_title" => null
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                    "field_h1" => null
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                    "breadcrumbs" => []
                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1568
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1605
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1677
                      #items: array:2 [ …2]
                      #escapeWhenCastingToString: false
                    }
                    "content" => Illuminate\Database\Eloquent\Collection {#1678
                      #items: array:2 [ …2]
                      #escapeWhenCastingToString: false
                    }
                    "next" => array:2 [
                      "refs" => "1439816"
                      "type" => "task"
                    ]
                    "previous" => array:2 [
                      "refs" => "1439814"
                      "type" => "task"
                    ]
                    "book" => Illuminate\Database\Eloquent\Collection {#1685
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "page" => array:2 [
                      "refs" => "1439441"
                      "type" => "book_page"
                    ]
                  ]
                  #original: array:24 [
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                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_page_start" => "123"
                    "field_page_end" => null
                    "field_url" => "/9-klass/fizika/izergin-uchebnik/24-1"
                    "field_display_title" => "1"
                    "field_outside_task" => null
                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1569}
                    "field_metatags_title" => null
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                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1568}
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                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1677}
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                    "next" => array:2 [
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                      "type" => "task"
                    ]
                    "book" => Illuminate\Database\Eloquent\Collection {#1685}
                    "page" => array:2 [
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                      "type" => "book_page"
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                  ]
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                  #dateFormat: null
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                  #touches: []
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                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
                1 => App\Models\Task {#1680
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
                    "id" => 1439816
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_page_start" => "123"
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                    "field_url" => "/9-klass/fizika/izergin-uchebnik/24-2"
                    "field_display_title" => "2"
                    "field_outside_task" => null
                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1679
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                      #escapeWhenCastingToString: false
                    }
                    "field_metatags_title" => null
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                    "breadcrumbs" => []
                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1687
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1683
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1681
                      #items: array:2 [ …2]
                      #escapeWhenCastingToString: false
                    }
                    "content" => Illuminate\Database\Eloquent\Collection {#1712
                      #items: array:2 [ …2]
                      #escapeWhenCastingToString: false
                    }
                    "next" => array:2 [
                      "refs" => "1439817"
                      "type" => "task"
                    ]
                    "previous" => array:2 [
                      "refs" => "1439815"
                      "type" => "task"
                    ]
                    "book" => Illuminate\Database\Eloquent\Collection {#1714
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "page" => array:2 [
                      "refs" => "1439441"
                      "type" => "book_page"
                    ]
                  ]
                  #original: array:24 [
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                    "field_url" => "/9-klass/fizika/izergin-uchebnik/24-2"
                    "field_display_title" => "2"
                    "field_outside_task" => null
                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1679}
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                    "content" => Illuminate\Database\Eloquent\Collection {#1712}
                    "next" => array:2 [
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                    "previous" => array:2 [
                      "refs" => "1439815"
                      "type" => "task"
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                    "book" => Illuminate\Database\Eloquent\Collection {#1714}
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                    0 => "*"
                  ]
                }
                2 => App\Models\Task {#1713
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
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                  #perPage: 15
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                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
                    "id" => 1439817
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
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                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1715
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "field_metatags_title" => null
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                    "breadcrumbs" => []
                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1716
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1717
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1718
                      #items: array:2 [ …2]
                      #escapeWhenCastingToString: false
                    }
                    "content" => Illuminate\Database\Eloquent\Collection {#1735
                      #items: array:2 [ …2]
                      #escapeWhenCastingToString: false
                    }
                    "next" => array:2 [
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                      "type" => "task"
                    ]
                    "previous" => array:2 [
                      "refs" => "1439816"
                      "type" => "task"
                    ]
                    "book" => Illuminate\Database\Eloquent\Collection {#1737
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                      #escapeWhenCastingToString: false
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                    "page" => array:2 [
                      "refs" => "1439441"
                      "type" => "book_page"
                    ]
                  ]
                  #original: array:24 [
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                    "field_url" => "/9-klass/fizika/izergin-uchebnik/24-3"
                    "field_display_title" => "3"
                    "field_outside_task" => null
                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1715}
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                    "next" => array:2 [
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                    "book" => Illuminate\Database\Eloquent\Collection {#1737}
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                    0 => "*"
                  ]
                }
                3 => App\Models\Task {#1736
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
                    "id" => 1439818
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
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                    "field_url" => "/9-klass/fizika/izergin-uchebnik/24-4"
                    "field_display_title" => "4"
                    "field_outside_task" => null
                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1738
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "field_metatags_title" => null
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                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1740
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                      #escapeWhenCastingToString: false
                    }
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1741
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                      #escapeWhenCastingToString: false
                    }
                    "content" => Illuminate\Database\Eloquent\Collection {#1758 …2}
                    "next" => array:2 [ …2]
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                    "book" => Illuminate\Database\Eloquent\Collection {#1760 …2}
                    "page" => array:2 [ …2]
                  ]
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                    "content" => Illuminate\Database\Eloquent\Collection {#1758 …2}
                    "next" => array:2 [ …2]
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}
№2 (с. 123)
Условие. №2 (с. 123)
скриншот условия
Физика, 9 класс Учебник, автор: Изергин Эдуард Тимофеевич, издательство Русское слово, Москва, 2019, страница 123, номер 2, Условие

2. Что такое колебательный контур?

Решение. №2 (с. 123)

2. Колебательный контур — это простейшая электрическая цепь, состоящая из соединенных между собой катушки индуктивности (элемента, обладающего индуктивностью $\text{L}$) и конденсатора (элемента, обладающего ёмкостью $\text{C}$). В такой системе могут возникать и поддерживаться свободные электромагнитные колебания.

Рассмотрим процесс колебаний в идеальном колебательном контуре, то есть в контуре, активное сопротивление которого пренебрежимо мало ($R \approx 0$).

  1. Пусть в начальный момент времени конденсатор заряжен до максимального напряжения $U_{max}$, а ток в цепи отсутствует. Вся энергия системы сосредоточена в электрическом поле конденсатора и равна $W_Э = \frac{C U_{max}^2}{2}$.

  2. Конденсатор начинает разряжаться через катушку индуктивности. В цепи возникает электрический ток, сила которого постепенно нарастает. Нарастающий ток создает в катушке переменное магнитное поле. Энергия электрического поля конденсатора начинает переходить в энергию магнитного поля катушки ($W_М = \frac{L I^2}{2}$).

  3. В момент, когда конденсатор полностью разрядится (напряжение на его обкладках станет равным нулю), сила тока в катушке достигнет своего максимального значения $I_{max}$. В этот момент вся энергия контура будет сосредоточена в магнитном поле катушки: $W_М = \frac{L I_{max}^2}{2}$.

  4. Несмотря на то, что конденсатор разрядился, ток в цепи не исчезает мгновенно из-за явления самоиндукции. Катушка индуктивности "препятствует" исчезновению тока, и он продолжает течь в том же направлении, перезаряжая конденсатор. Теперь обкладка, которая была заряжена положительно, становится отрицательной, и наоборот.

  5. Ток постепенно уменьшается до нуля. К моменту его полного исчезновения конденсатор окажется полностью перезаряженным, а напряжение на нем достигнет максимального значения, но с противоположным знаком ($-U_{max}$). Энергия магнитного поля катушки полностью перейдет обратно в энергию электрического поля конденсатора.

  6. Далее процесс повторяется в обратном направлении. Конденсатор снова начинает разряжаться, и в цепи возникает ток противоположного направления. Так происходят периодические превращения энергии электрического поля в энергию магнитного поля и обратно — электромагнитные колебания.

Период этих свободных колебаний в идеальном контуре определяется формулой Томсона:

$T = 2\pi\sqrt{LC}$

В реальном колебательном контуре всегда есть активное сопротивление, на котором происходит потеря энергии (выделение тепла). Поэтому свободные колебания в реальном контуре являются затухающими.

Ответ: Колебательный контур — это электрическая цепь, состоящая из катушки индуктивности и конденсатора, в которой могут происходить свободные электромагнитные колебания за счёт периодического превращения энергии электрического поля конденсатора в энергию магнитного поля катушки и обратно.

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