Номер 124, страница 218 - 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. Постоянный электрический ток. 30. Электрический ток в металлах, жидкостях, газах и вакууме. Полупроводники. Олимпиадные задачи - номер 124, страница 218.

App\Models\Task {#1030 // resources/views/models/task/default.blade.php
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  #table: "tasks"
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                          #connection: "mysql"
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                              "field_dative_case" => "задачнику"
                              "field_genitive_case" => "задачника"
                              "field_nominative_case" => "задачник"
                              "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 {#1063
                      #items: array:1 [
                        0 => App\Models\Term {#1064
                          #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 {#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: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 {#1067
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1068
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1069
                      #items: array:1 [
                        0 => App\Models\Term {#1070
                          #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 {#1071
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1072
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1073
                      #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 {#1074
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1075
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1076
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1077
                      #items: array:1 [
                        0 => App\Models\Term {#1078
                          #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 {#1050}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1051}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1054}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1056}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1060}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1061}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1063}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1065}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1067}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1068}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1069}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1071}
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1072}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1073}
                    "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 {#1074}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1075}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1076}
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1077}
                    "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 {#1079
              #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 {#1081}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1079}
          ]
          #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 {#1111
      #items: array:4 [
        0 => App\Models\Branch {#1121
          #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 {#1122
              #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 {#1123
              #items: array:1 [
                0 => App\Models\Book {#1048}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1124
              #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 {#1122}
            "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 {#1123}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1124}
          ]
          #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 {#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" => 1319350
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Постоянный электрический ток"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1126
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "188"
            "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 {#1048}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1128
              #items: array:1 [
                0 => App\Models\Branch {#1045}
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1319350
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Постоянный электрический ток"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1126}
            "field_page_start" => "188"
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            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1127}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1128}
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            0 => "*"
          ]
        }
        2 => 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" => 1319361
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
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            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1130
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              #escapeWhenCastingToString: false
            }
            "field_page_start" => "215"
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            "field_branch_cover" => []
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            "book" => Illuminate\Database\Eloquent\Collection {#1131
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                0 => App\Models\Book {#1048}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1140
              #items: array:1 [
                0 => App\Models\Branch {#1139
                  #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" => 1319350
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Постоянный электрический ток"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1141
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                      #escapeWhenCastingToString: false
                    }
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                    "book" => Illuminate\Database\Eloquent\Collection {#1142
                      #items: array:1 [
                        0 => App\Models\Book {#1048}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1143
                      #items: array:1 [
                        0 => App\Models\Branch {#1045}
                      ]
                      #escapeWhenCastingToString: false
                    }
                  ]
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                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1141}
                    "field_page_start" => "188"
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                    "book" => Illuminate\Database\Eloquent\Collection {#1142}
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                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
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            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1130}
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          ]
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          #hidden: []
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          #guarded: array:1 [
            0 => "*"
          ]
        }
        3 => 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" => 1319363
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Олимпиадные задачи"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1132
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "218"
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            "field_display_branch_in_title" => "1"
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            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
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            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1136
              #items: array:1 [
                0 => App\Models\Book {#1048}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1149
              #items: array:1 [
                0 => App\Models\Branch {#1148
                  #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" => 1319361
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
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                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1150
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "215"
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                    "book" => Illuminate\Database\Eloquent\Collection {#1151
                      #items: array:1 [
                        0 => App\Models\Book {#1048}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1152
                      #items: array:1 [
                        0 => App\Models\Branch {#1139}
                      ]
                      #escapeWhenCastingToString: false
                    }
                  ]
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                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1150}
                    "field_page_start" => "215"
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                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1152}
                  ]
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                    0 => "*"
                  ]
                }
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              #escapeWhenCastingToString: false
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          #original: array:24 [
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            "updated_at" => null
            "field_display_title" => "Олимпиадные задачи"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1132}
            "field_page_start" => "218"
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          ]
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            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "content" => Illuminate\Database\Eloquent\Collection {#1038
      #items: array:2 [
        0 => App\Models\Element {#1102
          #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" => 1494102
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1092
              #items: array:1 [
                0 => App\Models\Edition {#1101
                  #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 {#1098
                      #items: array:1 [
                        0 => App\Models\Term {#1100
                          #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 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
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                          #attributeCastCache: []
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                          +timestamps: true
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                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #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 {#1099
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1097
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_process_formula" => "katex"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1096
                      #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"
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                    "field_solution_author" => "Автор"
                    "field_moderator" => "stas"
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                    "field_root_dir" => "0-"
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                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1097}
                    "field_process_formula" => "katex"
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                  ]
                  #changes: []
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #touches: []
                  +timestamps: true
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                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "1319745"
              "type" => "task"
            ]
            "text" => "<p><strong>O24.</strong> Пучок электронов, разогнанных напряжением $U_1 = 5 \text{ кВ}$, влетает в плоский конденсатор посередине между пластинами и параллельно им. Длина конденсатора $l = 10 \text{ см}$, расстояние между пластинами $d = 10 \text{ мм}$. При каком наименьшем напряжении $U_2$ на конденсаторе электроны не будут вылетать из него?</p><p>☑ 100 В.</p><p><strong><em>Решение.</em></strong> Движение электрона, влетевшего в конденсатор параллельно его пластинам, напоминает движение тела, брошенного горизонтально (см. рисунок). Электроны не будут вылетать из конденсатора, если $at^2/2 \ge d/2$. Ускорение $a = \frac{eE}{m_e} = \frac{eU_2}{dm_e}$, а время движения электрона в конденсаторе $t = \frac{l}{v} = l\sqrt{\frac{m_e}{2eU_1}}$. Отсюда $U_2 = 2d^2U_1/l^2$.</p>"
            "img" => array:2 [
              0 => array:5 [
                "name" => "124-1.jpg"
                "alt" => null
                "width" => "1407"
                "height" => 1092
                "path" => "/media/fizika_10/gelfgat-z/0-olimp/124-1.webp?ts=1756251262"
              ]
              1 => array:5 [
                "name" => "124-2.jpg"
                "alt" => null
                "width" => "1322"
                "height" => 429
                "path" => "/media/fizika_10/gelfgat-z/0-olimp/124-2.webp?ts=1756251262"
              ]
            ]
          ]
          #original: array:7 [
            "id" => 1494102
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1092}
            "task" => array:2 [
              "refs" => "1319745"
              "type" => "task"
            ]
            "text" => "<p><strong>O24.</strong> Пучок электронов, разогнанных напряжением $U_1 = 5 \text{ кВ}$, влетает в плоский конденсатор посередине между пластинами и параллельно им. Длина конденсатора $l = 10 \text{ см}$, расстояние между пластинами $d = 10 \text{ мм}$. При каком наименьшем напряжении $U_2$ на конденсаторе электроны не будут вылетать из него?</p><p>☑ 100 В.</p><p><strong><em>Решение.</em></strong> Движение электрона, влетевшего в конденсатор параллельно его пластинам, напоминает движение тела, брошенного горизонтально (см. рисунок). Электроны не будут вылетать из конденсатора, если $at^2/2 \ge d/2$. Ускорение $a = \frac{eE}{m_e} = \frac{eU_2}{dm_e}$, а время движения электрона в конденсаторе $t = \frac{l}{v} = l\sqrt{\frac{m_e}{2eU_1}}$. Отсюда $U_2 = 2d^2U_1/l^2$.</p>"
            "img" => array:2 [
              0 => array:5 [
                "name" => "124-1.jpg"
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            "text" => "<p><strong>Дано:</strong></p><p>$U_1 = 5 \text{ кВ}$</p><p>$l = 10 \text{ см}$</p><p>$d = 10 \text{ мм}$</p><p><em>Перевод в систему СИ:</em></p><p>$U_1 = 5 \cdot 10^3 \text{ В}$</p><p>$l = 0.1 \text{ м}$</p><p>$d = 0.01 \text{ м}$</p><p><strong>Найти:</strong></p><p>$U_2$</p><p><strong>Решение:</strong></p><p><strong>1.</strong> Сначала найдем скорость, с которой электрон влетает в конденсатор. Электрон разгоняется напряжением $U_1$, и его кинетическая энергия равна работе электрического поля:</p><p>$\frac{m_e v^2}{2} = eU_1$</p><p>где $m_e$ — масса электрона, $e$ — заряд электрона, $v$ — его скорость.</p><p>Эта скорость направлена горизонтально, параллельно пластинам конденсатора.</p><p><strong>2.</strong> Внутри конденсатора на электрон действует однородное электрическое поле, направленное перпендикулярно пластинам. Напряженность этого поля $E = \frac{U_2}{d}$.</p><p>Сила, действующая на электрон в вертикальном направлении: $F_y = eE = \frac{eU_2}{d}$.</p><p>Эта сила сообщает электрону постоянное вертикальное ускорение: $a_y = \frac{F_y}{m_e} = \frac{eU_2}{dm_e}$.</p><p><strong>3.</strong> Движение электрона можно рассматривать как сумму двух независимых движений: равномерного по горизонтали (вдоль пластин) и равноускоренного по вертикали (перпендикулярно пластинам).</p><p>Время полета электрона внутри конденсатора определяется его горизонтальной скоростью $v$ и длиной пластин $l$:</p><p>$t = \frac{l}{v}$</p><p><strong>4.</strong> Электрон влетает в конденсатор посередине. Чтобы он не вылетел, его вертикальное смещение $y$ за время полета $t$ должно быть как минимум равно половине расстояния между пластинами, то есть $\frac{d}{2}$. Минимальное напряжение $U_2$ соответствует предельному случаю, когда электрон попадает точно на край пластины.</p><p>Вертикальное смещение при равноускоренном движении с нулевой начальной скоростью: $y = \frac{a_y t^2}{2}$.</p><p>Приравниваем $y$ к $\frac{d}{2}$:</p><p>$\frac{d}{2} = \frac{a_y t^2}{2}$</p><p>$d = a_y t^2$</p><p><strong>5.</strong> Подставим в это уравнение выражения для $a_y$ и $t$:</p><p>$d = \left(\frac{eU_2}{dm_e}\right) \left(\frac{l}{v}\right)^2 = \frac{eU_2 l^2}{dm_e v^2}$</p><p>Из первого шага мы знаем, что $m_e v^2 = 2eU_1$. Подставим это в знаменатель:</p><p>$d = \frac{eU_2 l^2}{d(2eU_1)}$</p><p>Сократим заряд электрона $e$:</p><p>$d = \frac{U_2 l^2}{2d U_1}$</p><p><strong>6.</strong> Выразим из полученного уравнения искомое напряжение $U_2$:</p><p>$2d^2 U_1 = U_2 l^2$</p><p>$U_2 = \frac{2d^2 U_1}{l^2}$</p><p><strong>7.</strong> Подставим числовые значения из системы СИ:</p><p>$U_2 = \frac{2 \cdot (0.01 \text{ м})^2 \cdot (5 \cdot 10^3 \text{ В})}{(0.1 \text{ м})^2} = \frac{2 \cdot 10^{-4} \text{ м}^2 \cdot 5 \cdot 10^3 \text{ В}}{10^{-2} \text{ м}^2} = \frac{10 \cdot 10^{-1} \text{ В}}{10^{-2}} = \frac{1}{10^{-2}} \text{ В} = 100 \text{ В}$</p><p><strong>Ответ:</strong> $100 \text{ В}$.</p>"
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            "text" => "<p><strong>Дано:</strong></p><p>$U_1 = 5 \text{ кВ}$</p><p>$l = 10 \text{ см}$</p><p>$d = 10 \text{ мм}$</p><p><em>Перевод в систему СИ:</em></p><p>$U_1 = 5 \cdot 10^3 \text{ В}$</p><p>$l = 0.1 \text{ м}$</p><p>$d = 0.01 \text{ м}$</p><p><strong>Найти:</strong></p><p>$U_2$</p><p><strong>Решение:</strong></p><p><strong>1.</strong> Сначала найдем скорость, с которой электрон влетает в конденсатор. Электрон разгоняется напряжением $U_1$, и его кинетическая энергия равна работе электрического поля:</p><p>$\frac{m_e v^2}{2} = eU_1$</p><p>где $m_e$ — масса электрона, $e$ — заряд электрона, $v$ — его скорость.</p><p>Эта скорость направлена горизонтально, параллельно пластинам конденсатора.</p><p><strong>2.</strong> Внутри конденсатора на электрон действует однородное электрическое поле, направленное перпендикулярно пластинам. Напряженность этого поля $E = \frac{U_2}{d}$.</p><p>Сила, действующая на электрон в вертикальном направлении: $F_y = eE = \frac{eU_2}{d}$.</p><p>Эта сила сообщает электрону постоянное вертикальное ускорение: $a_y = \frac{F_y}{m_e} = \frac{eU_2}{dm_e}$.</p><p><strong>3.</strong> Движение электрона можно рассматривать как сумму двух независимых движений: равномерного по горизонтали (вдоль пластин) и равноускоренного по вертикали (перпендикулярно пластинам).</p><p>Время полета электрона внутри конденсатора определяется его горизонтальной скоростью $v$ и длиной пластин $l$:</p><p>$t = \frac{l}{v}$</p><p><strong>4.</strong> Электрон влетает в конденсатор посередине. Чтобы он не вылетел, его вертикальное смещение $y$ за время полета $t$ должно быть как минимум равно половине расстояния между пластинами, то есть $\frac{d}{2}$. Минимальное напряжение $U_2$ соответствует предельному случаю, когда электрон попадает точно на край пластины.</p><p>Вертикальное смещение при равноускоренном движении с нулевой начальной скоростью: $y = \frac{a_y t^2}{2}$.</p><p>Приравниваем $y$ к $\frac{d}{2}$:</p><p>$\frac{d}{2} = \frac{a_y t^2}{2}$</p><p>$d = a_y t^2$</p><p><strong>5.</strong> Подставим в это уравнение выражения для $a_y$ и $t$:</p><p>$d = \left(\frac{eU_2}{dm_e}\right) \left(\frac{l}{v}\right)^2 = \frac{eU_2 l^2}{dm_e v^2}$</p><p>Из первого шага мы знаем, что $m_e v^2 = 2eU_1$. Подставим это в знаменатель:</p><p>$d = \frac{eU_2 l^2}{d(2eU_1)}$</p><p>Сократим заряд электрона $e$:</p><p>$d = \frac{U_2 l^2}{2d U_1}$</p><p><strong>6.</strong> Выразим из полученного уравнения искомое напряжение $U_2$:</p><p>$2d^2 U_1 = U_2 l^2$</p><p>$U_2 = \frac{2d^2 U_1}{l^2}$</p><p><strong>7.</strong> Подставим числовые значения из системы СИ:</p><p>$U_2 = \frac{2 \cdot (0.01 \text{ м})^2 \cdot (5 \cdot 10^3 \text{ В})}{(0.1 \text{ м})^2} = \frac{2 \cdot 10^{-4} \text{ м}^2 \cdot 5 \cdot 10^3 \text{ В}}{10^{-2} \text{ м}^2} = \frac{10 \cdot 10^{-1} \text{ В}}{10^{-2}} = \frac{1}{10^{-2}} \text{ В} = 100 \text{ В}$</p><p><strong>Ответ:</strong> $100 \text{ В}$.</p>"
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№124 (с. 218)
Условие. №124 (с. 218)
скриншот условия
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 218, номер 124, Условие
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 218, номер 124, Условие (продолжение 2)

O24. Пучок электронов, разогнанных напряжением $U_1 = 5 \text{ кВ}$, влетает в плоский конденсатор посередине между пластинами и параллельно им. Длина конденсатора $l = 10 \text{ см}$, расстояние между пластинами $d = 10 \text{ мм}$. При каком наименьшем напряжении $U_2$ на конденсаторе электроны не будут вылетать из него?

☑ 100 В.

Решение. Движение электрона, влетевшего в конденсатор параллельно его пластинам, напоминает движение тела, брошенного горизонтально (см. рисунок). Электроны не будут вылетать из конденсатора, если $at^2/2 \ge d/2$. Ускорение $a = \frac{eE}{m_e} = \frac{eU_2}{dm_e}$, а время движения электрона в конденсаторе $t = \frac{l}{v} = l\sqrt{\frac{m_e}{2eU_1}}$. Отсюда $U_2 = 2d^2U_1/l^2$.

Решение. №124 (с. 218)

Дано:

$U_1 = 5 \text{ кВ}$

$l = 10 \text{ см}$

$d = 10 \text{ мм}$

Перевод в систему СИ:

$U_1 = 5 \cdot 10^3 \text{ В}$

$l = 0.1 \text{ м}$

$d = 0.01 \text{ м}$

Найти:

$U_2$

Решение:

1. Сначала найдем скорость, с которой электрон влетает в конденсатор. Электрон разгоняется напряжением $U_1$, и его кинетическая энергия равна работе электрического поля:

$\frac{m_e v^2}{2} = eU_1$

где $m_e$ — масса электрона, $e$ — заряд электрона, $v$ — его скорость.

Эта скорость направлена горизонтально, параллельно пластинам конденсатора.

2. Внутри конденсатора на электрон действует однородное электрическое поле, направленное перпендикулярно пластинам. Напряженность этого поля $E = \frac{U_2}{d}$.

Сила, действующая на электрон в вертикальном направлении: $F_y = eE = \frac{eU_2}{d}$.

Эта сила сообщает электрону постоянное вертикальное ускорение: $a_y = \frac{F_y}{m_e} = \frac{eU_2}{dm_e}$.

3. Движение электрона можно рассматривать как сумму двух независимых движений: равномерного по горизонтали (вдоль пластин) и равноускоренного по вертикали (перпендикулярно пластинам).

Время полета электрона внутри конденсатора определяется его горизонтальной скоростью $v$ и длиной пластин $l$:

$t = \frac{l}{v}$

4. Электрон влетает в конденсатор посередине. Чтобы он не вылетел, его вертикальное смещение $y$ за время полета $t$ должно быть как минимум равно половине расстояния между пластинами, то есть $\frac{d}{2}$. Минимальное напряжение $U_2$ соответствует предельному случаю, когда электрон попадает точно на край пластины.

Вертикальное смещение при равноускоренном движении с нулевой начальной скоростью: $y = \frac{a_y t^2}{2}$.

Приравниваем $y$ к $\frac{d}{2}$:

$\frac{d}{2} = \frac{a_y t^2}{2}$

$d = a_y t^2$

5. Подставим в это уравнение выражения для $a_y$ и $t$:

$d = \left(\frac{eU_2}{dm_e}\right) \left(\frac{l}{v}\right)^2 = \frac{eU_2 l^2}{dm_e v^2}$

Из первого шага мы знаем, что $m_e v^2 = 2eU_1$. Подставим это в знаменатель:

$d = \frac{eU_2 l^2}{d(2eU_1)}$

Сократим заряд электрона $e$:

$d = \frac{U_2 l^2}{2d U_1}$

6. Выразим из полученного уравнения искомое напряжение $U_2$:

$2d^2 U_1 = U_2 l^2$

$U_2 = \frac{2d^2 U_1}{l^2}$

7. Подставим числовые значения из системы СИ:

$U_2 = \frac{2 \cdot (0.01 \text{ м})^2 \cdot (5 \cdot 10^3 \text{ В})}{(0.1 \text{ м})^2} = \frac{2 \cdot 10^{-4} \text{ м}^2 \cdot 5 \cdot 10^3 \text{ В}}{10^{-2} \text{ м}^2} = \frac{10 \cdot 10^{-1} \text{ В}}{10^{-2}} = \frac{1}{10^{-2}} \text{ В} = 100 \text{ В}$

Ответ: $100 \text{ В}$.

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