Это любопытно, страница 227 - гдз по физике 8 класс учебник Пёрышкин

Физика, 8 класс Учебник, автор: Пёрышкин И М, издательство Просвещение, Москва, 2023, белого цвета

Авторы: Пёрышкин И. М.

Тип: Учебник

Издательство: Просвещение

Год издания: 2023 - 2026

Уровень обучения: базовый

Цвет обложки: белый с градусником

ISBN: 978-5-09-102555-2

Допущено Министерством просвещения Российской Федерации

Глава 3. Электромагнитные явления. Параграф 62. Передача электрической энергии. Вопросы после параграфа - страница 227.

App\Models\Task {#1024 // resources/views/models/task/default.blade.php
  #connection: "mysql"
  #table: "tasks"
  #primaryKey: "id"
  #keyType: "int"
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  #with: []
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  #perPage: 15
  +exists: true
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  #escapeWhenCastingToString: false
  #attributes: array:24 [
    "id" => 599426
    "created_at" => "2026-04-10 13:58:26"
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    "field_page_end" => null
    "field_url" => "/8-klass/fizika/peryshkin-uchebnik/62-2-1"
    "field_display_title" => "Это любопытно"
    "field_outside_task" => null
    "field_task_type" => Illuminate\Database\Eloquent\Collection {#331
      #items: []
      #escapeWhenCastingToString: false
    }
    "field_metatags_title" => 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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      #items: array:1 [
        0 => App\Models\Branch {#342
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          #table: "branches"
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          #keyType: "int"
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          #attributes: array:24 [
            "id" => 598741
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
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            "field_branch_order" => "3"
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                      #items: array:1 [
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                          #connection: "mysql"
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                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
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                        0 => App\Models\Term {#1038
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                            "created_at" => "2026-04-10 13:58:26"
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                          ]
                          #original: array:6 [
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                            "created_at" => "2026-04-10 13:58:26"
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                        0 => App\Models\Term {#1040
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                              "field_genitive_case" => "базового"
                              "field_nominative_case" => "базовый"
                              "field_prepositional_case" => "базовом"
                            ]
                            "field_translit" => "bazovyy"
                          ]
                          #original: array:6 [
                            "id" => 38
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "базовый"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "базовый"
                              "field_creative_case" => "базовым"
                              "field_dative_case" => "базовому"
                              "field_genitive_case" => "базового"
                              "field_nominative_case" => "базовый"
                              "field_prepositional_case" => "базовом"
                            ]
                            "field_translit" => "bazovyy"
                          ]
                          #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 {#1052
                      #items: array:1 [
                        0 => App\Models\Term {#1053
                          #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" => 25
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "ФГОС (новый)"
                            "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" => "красный"
                            "field_end_year" => "2027"
                            "field_start_year" => "2023"
                            "field_translit" => "fgos"
                            "field_type" => "новый"
                          ]
                          #original: array:10 [
                            "id" => 25
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "ФГОС (новый)"
                            "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" => "красный"
                            "field_end_year" => "2027"
                            "field_start_year" => "2023"
                            "field_translit" => "fgos"
                            "field_type" => "новый"
                          ]
                          #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" => "3"
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1054
                      #items: array:1 [
                        0 => App\Models\Term {#1055
                          #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" => 34
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "переработанное"
                            "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" => "pererabotannoe"
                          ]
                          #original: array:6 [
                            "id" => 34
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "переработанное"
                            "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" => "pererabotannoe"
                          ]
                          #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_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1056
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => "с градусником"
                    "field_publication_year" => "2023"
                    "field_publication_year_until" => null
                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => null
                    "field_allowed" => "Допущено Министерством просвещения Российской Федерации"
                    "field_reserve_field" => null
                    "field_link_to_source" => null
                    "field_tasks_count" => "706"
                    "field_priority" => "2"
                    "field_default_folder" => "/fizika_08/Peryshkin-u23/"
                    "field_isbn" => "978-5-09-102555-2"
                    "field_cover" => array:1 [
                      0 => "/media/fizika_08/Peryshkin-u23/covers/cover1.webp?ts=1737917825"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/fizika_08/Peryshkin-u23/covers/cover1.webp?ts=1737917825"
                        "alt" => ""
                        "width" => "1350"
                        "height" => "1772"
                      ]
                    ]
                    "field_popular_book" => null
                    "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" => "/8-klass/fizika/peryshkin-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" => 45
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "белый"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "белый"
                              "field_creative_case" => "белым"
                              "field_dative_case" => "белому"
                              "field_genitive_case" => "белого"
                              "field_nominative_case" => "белый"
                              "field_prepositional_case" => "белом"
                            ]
                            "field_translit" => "belyy"
                          ]
                          #original: array:6 [
                            "id" => 45
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "белый"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "белый"
                              "field_creative_case" => "белым"
                              "field_dative_case" => "белому"
                              "field_genitive_case" => "белого"
                              "field_nominative_case" => "белый"
                              "field_prepositional_case" => "белом"
                            ]
                            "field_translit" => "belyy"
                          ]
                          #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" => 379
                      "subject" => 556
                      "class_subject" => 492
                    ]
                  ]
                  #original: array:50 [
                    "id" => 51
                    "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 {#1032}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1035}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1037}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1039}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1041}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1042}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1044}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1046}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1048}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1049}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1050}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1052}
                    "field_publication_number" => "3"
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1054}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1056}
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => "с градусником"
                    "field_publication_year" => "2023"
                    "field_publication_year_until" => null
                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => null
                    "field_allowed" => "Допущено Министерством просвещения Российской Федерации"
                    "field_reserve_field" => null
                    "field_link_to_source" => null
                    "field_tasks_count" => "706"
                    "field_priority" => "2"
                    "field_default_folder" => "/fizika_08/Peryshkin-u23/"
                    "field_isbn" => "978-5-09-102555-2"
                    "field_cover" => array:1 [
                      0 => "/media/fizika_08/Peryshkin-u23/covers/cover1.webp?ts=1737917825"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/fizika_08/Peryshkin-u23/covers/cover1.webp?ts=1737917825"
                        "alt" => ""
                        "width" => "1350"
                        "height" => "1772"
                      ]
                    ]
                    "field_popular_book" => null
                    "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" => "/8-klass/fizika/peryshkin-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" => 379
                      "subject" => 556
                      "class_subject" => 492
                    ]
                  ]
                  #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 {#1062
              #items: []
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 598741
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Электромагнитные явления"
            "field_branch_order" => "3"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1023}
            "field_page_start" => "183"
            "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 {#1033}
            "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:3 [
        0 => App\Models\Branch {#342}
        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" => 598777
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Передача электрической энергии"
            "field_branch_order" => "62"
            "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" => "223"
            "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 {#1030}
              ]
              #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" => 598741
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Электромагнитные явления"
                    "field_branch_order" => "3"
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1070
                      #items: array:1 [
                        0 => App\Models\Term {#1071
                          #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 [ …7]
                          #original: array:7 [ …7]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                           …11
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "183"
                    "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 {#1072
                      #items: array:1 [
                        0 => App\Models\Book {#1073 …30}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1103
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                  ]
                  #original: array:24 [
                    "id" => 598741
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Электромагнитные явления"
                    "field_branch_order" => "3"
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1070}
                    "field_page_start" => "183"
                    "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 {#1072}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1103}
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 598777
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Передача электрической энергии"
            "field_branch_order" => "62"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1065}
            "field_page_start" => "223"
            "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}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1068}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        2 => App\Models\Branch {#1104
          #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" => 598778
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Вопросы после параграфа"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1105
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "226"
            "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 {#1106
              #items: array:1 [
                0 => App\Models\Book {#1030}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1107
              #items: array:1 [
                0 => App\Models\Branch {#1108
                  #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" => 598777
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Передача электрической энергии"
                    "field_branch_order" => "62"
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1109
                      #items: array:1 [
                        0 => App\Models\Term {#1066}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "223"
                    "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 {#1110
                      #items: array:1 [
                        0 => App\Models\Book {#1030}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1111
                      #items: array:1 [
                        0 => App\Models\Branch {#1069}
                      ]
                      #escapeWhenCastingToString: false
                    }
                  ]
                  #original: array:24 [
                    "id" => 598777
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Передача электрической энергии"
                    "field_branch_order" => "62"
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1109}
                    "field_page_start" => "223"
                    "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 {#1110}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1111}
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 598778
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Вопросы после параграфа"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1105}
            "field_page_start" => "226"
            "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 {#1106}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1107}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "content" => Illuminate\Database\Eloquent\Collection {#1112
      #items: array:4 [
        0 => App\Models\Element {#1113
          #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" => 746389
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1114
              #items: array:1 [
                0 => App\Models\Edition {#1115
                  #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" => 1636
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Условие"
                    "field_order" => "1"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1116
                      #items: array:1 [
                        0 => App\Models\Term {#1117 …30}
                      ]
                      #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 {#1118
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1119
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1120
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_content_source" => null
                  ]
                  #original: array:21 [
                    "id" => 1636
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Условие"
                    "field_order" => "1"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1116}
                    "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 {#1118}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1119}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1120}
                    "field_content_source" => 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
            }
            "task" => array:2 [
              "refs" => "599426"
              "type" => "task"
            ]
            "text" => "<p> Высоковольтные ЛЭП постоянного тока позволяют передавать электроэнергию с меньшими потерями, чем ЛЭП переменного тока. Как вы думаете, с чем связано повсеместное применение именно ЛЭП переменного тока? </p>"
            "img" => array:1 [
              0 => array:5 [
                "name" => "1-1.png"
                "alt" => null
                "width" => "710"
                "height" => 157
                "path" => "/media/fizika_08/Peryshkin-u23/0-62-2/1-1.webp?ts=1738081073"
              ]
            ]
          ]
          #original: array:7 [
            "id" => 746389
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1114}
            "task" => array:2 [
              "refs" => "599426"
              "type" => "task"
            ]
            "text" => "<p> Высоковольтные ЛЭП постоянного тока позволяют передавать электроэнергию с меньшими потерями, чем ЛЭП переменного тока. Как вы думаете, с чем связано повсеместное применение именно ЛЭП переменного тока? </p>"
            "img" => array:1 [
              0 => array:5 [
                "name" => "1-1.png"
                "alt" => null
                "width" => "710"
                "height" => 157
                "path" => "/media/fizika_08/Peryshkin-u23/0-62-2/1-1.webp?ts=1738081073"
              ]
            ]
          ]
          #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\Element {#1121
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:6 [
            "id" => 746708
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1122
              #items: array:1 [
                0 => App\Models\Edition {#1123
                  #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" => 1637
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 1"
                    "field_order" => "2"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1124
                      #items: array:1 [
                        0 => App\Models\Term {#1125 …30}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_content_type" => "free"
                    "field_content_mode" => "image"
                    "field_page_content_mode" => ""
                    "field_content_text_checked" => "0"
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Колесникович"
                    "field_moderator" => "stas"
                    "field_edition_type" => "solution"
                    "field_root_dir" => "1-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1126
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1127
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1128
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_content_source" => null
                  ]
                  #original: array:21 [
                    "id" => 1637
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 1"
                    "field_order" => "2"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1124}
                    "field_content_type" => "free"
                    "field_content_mode" => "image"
                    "field_page_content_mode" => ""
                    "field_content_text_checked" => "0"
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Колесникович"
                    "field_moderator" => "stas"
                    "field_edition_type" => "solution"
                    "field_root_dir" => "1-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1126}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1127}
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1128}
                    "field_content_source" => 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
            }
            "task" => array:2 [
              "refs" => "599426"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "1-1.jpg"
                "alt" => null
                "width" => "2076"
                "height" => 770
                "path" => "/media/fizika_08/Peryshkin-u23/1-62-2/1-1.webp?ts=1738081130"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 746708
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1122}
            "task" => array:2 [
              "refs" => "599426"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "1-1.jpg"
                "alt" => null
                "width" => "2076"
                "height" => 770
                "path" => "/media/fizika_08/Peryshkin-u23/1-62-2/1-1.webp?ts=1738081130"
              ]
            ]
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        2 => App\Models\Element {#1129
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:6 [
            "id" => 747614
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1130
              #items: array:1 [
                0 => App\Models\Edition {#1131
                  #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" => 1639
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 3"
                    "field_order" => "4"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1132
                      #items: array:1 [
                        0 => App\Models\Term {#1133 …30}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_content_type" => "free"
                    "field_content_mode" => "image"
                    "field_page_content_mode" => ""
                    "field_content_text_checked" => "0"
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Неизвестный"
                    "field_moderator" => "stas"
                    "field_edition_type" => "solution"
                    "field_root_dir" => "2-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1134
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1135
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_process_formula" => ""
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1136
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_content_source" => null
                  ]
                  #original: array:21 [
                    "id" => 1639
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение 3"
                    "field_order" => "4"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1132}
                    "field_content_type" => "free"
                    "field_content_mode" => "image"
                    "field_page_content_mode" => ""
                    "field_content_text_checked" => "0"
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Неизвестный"
                    "field_moderator" => "stas"
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            "text" => "<p>Несмотря на то, что высоковольтные линии электропередачи (ЛЭП) постоянного тока действительно обладают меньшими потерями при передаче на сверхдальние расстояния, повсеместное применение получили ЛЭП переменного тока. Это связано с ключевым преимуществом переменного тока: возможностью легко и с высоким КПД изменять напряжение с помощью трансформаторов.</p><p>Рассмотрим процесс передачи электроэнергии от станции до потребителя:</p><ol><li><strong>Производство электроэнергии.</strong> Электроэнергия на электростанциях вырабатывается генераторами переменного тока при относительно невысоких напряжениях (например, 10–25 кВ).\t</li><li><strong>Передача на большие расстояния.</strong> Для эффективной передачи энергии на большие расстояния необходимо минимизировать потери. Потери мощности в проводах определяются законом Джоуля-Ленца: $P_{потерь} = I^2 \cdot R$, где $I$ — сила тока, а $R$ — сопротивление линии. Передаваемая же мощность равна $P = U \cdot I$. Чтобы передать ту же мощность $P$ при меньшей силе тока $I$ (и, следовательно, значительно уменьшить потери), необходимо увеличить напряжение $U$.\t</li><li><strong>Трансформация напряжения.</strong> Именно здесь проявляется главное преимущество переменного тока. Трансформаторы, работающие на принципе электромагнитной индукции, позволяют очень эффективно (с КПД более 99%) повышать напряжение перед передачей (например, до 500-750 кВ) и понижать его в несколько этапов перед подачей потребителям (до бытовых 220/380 В). Трансформатор работает только с переменным током, так как для индуцирования ЭДС во вторичной обмотке необходимо переменное магнитное поле, создаваемое переменным током в первичной обмотке.\t</li><li><strong>Сложность систем постоянного тока.</strong> Для передачи постоянного тока на высоком напряжении необходимо сначала преобразовать переменный ток от генератора в постоянный с помощью дорогостоящих и сложных выпрямителей. Затем, на приёмном конце линии, постоянный ток нужно снова преобразовать в переменный с помощью инверторов, чтобы его можно было трансформировать до уровней, пригодных для конечных потребителей. Эти преобразователи (выпрямители и инверторы) исторически были и остаются значительно сложнее, дороже и менее надежными, чем простые и надежные трансформаторы.\t</li></ol><p>Таким образом, хотя сами линии постоянного тока экономичнее для очень длинных дистанций (где экономия на потерях перекрывает стоимость преобразователей), для создания разветвлённой сети энергоснабжения, охватывающей города и предприятия с множеством этапов понижения напряжения, система переменного тока оказывается значительно проще и дешевле в реализации и эксплуатации.</p><p><strong>Ответ:</strong> Повсеместное применение ЛЭП переменного тока связано с тем, что напряжение переменного тока можно легко и эффективно изменять (повышать для передачи и понижать для потребления) с помощью простых, дешевых и надежных устройств — трансформаторов. Это позволяет минимизировать потери энергии в проводах при передаче на большие расстояния и безопасно доставлять ее конечным потребителям. Преобразование же напряжения в сетях постоянного тока требует значительно более сложного и дорогого оборудования.</p>"
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            "task" => array:2 [
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              "type" => "task"
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            "text" => "<p>Несмотря на то, что высоковольтные линии электропередачи (ЛЭП) постоянного тока действительно обладают меньшими потерями при передаче на сверхдальние расстояния, повсеместное применение получили ЛЭП переменного тока. Это связано с ключевым преимуществом переменного тока: возможностью легко и с высоким КПД изменять напряжение с помощью трансформаторов.</p><p>Рассмотрим процесс передачи электроэнергии от станции до потребителя:</p><ol><li><strong>Производство электроэнергии.</strong> Электроэнергия на электростанциях вырабатывается генераторами переменного тока при относительно невысоких напряжениях (например, 10–25 кВ).\t</li><li><strong>Передача на большие расстояния.</strong> Для эффективной передачи энергии на большие расстояния необходимо минимизировать потери. Потери мощности в проводах определяются законом Джоуля-Ленца: $P_{потерь} = I^2 \cdot R$, где $I$ — сила тока, а $R$ — сопротивление линии. Передаваемая же мощность равна $P = U \cdot I$. Чтобы передать ту же мощность $P$ при меньшей силе тока $I$ (и, следовательно, значительно уменьшить потери), необходимо увеличить напряжение $U$.\t</li><li><strong>Трансформация напряжения.</strong> Именно здесь проявляется главное преимущество переменного тока. Трансформаторы, работающие на принципе электромагнитной индукции, позволяют очень эффективно (с КПД более 99%) повышать напряжение перед передачей (например, до 500-750 кВ) и понижать его в несколько этапов перед подачей потребителям (до бытовых 220/380 В). Трансформатор работает только с переменным током, так как для индуцирования ЭДС во вторичной обмотке необходимо переменное магнитное поле, создаваемое переменным током в первичной обмотке.\t</li><li><strong>Сложность систем постоянного тока.</strong> Для передачи постоянного тока на высоком напряжении необходимо сначала преобразовать переменный ток от генератора в постоянный с помощью дорогостоящих и сложных выпрямителей. Затем, на приёмном конце линии, постоянный ток нужно снова преобразовать в переменный с помощью инверторов, чтобы его можно было трансформировать до уровней, пригодных для конечных потребителей. Эти преобразователи (выпрямители и инверторы) исторически были и остаются значительно сложнее, дороже и менее надежными, чем простые и надежные трансформаторы.\t</li></ol><p>Таким образом, хотя сами линии постоянного тока экономичнее для очень длинных дистанций (где экономия на потерях перекрывает стоимость преобразователей), для создания разветвлённой сети энергоснабжения, охватывающей города и предприятия с множеством этапов понижения напряжения, система переменного тока оказывается значительно проще и дешевле в реализации и эксплуатации.</p><p><strong>Ответ:</strong> Повсеместное применение ЛЭП переменного тока связано с тем, что напряжение переменного тока можно легко и эффективно изменять (повышать для передачи и понижать для потребления) с помощью простых, дешевых и надежных устройств — трансформаторов. Это позволяет минимизировать потери энергии в проводах при передаче на большие расстояния и безопасно доставлять ее конечным потребителям. Преобразование же напряжения в сетях постоянного тока требует значительно более сложного и дорогого оборудования.</p>"
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Это любопытно (с. 227)
Условие. Это любопытно (с. 227)
скриншот условия
Физика, 8 класс Учебник, автор: Пёрышкин И М, издательство Просвещение, Москва, 2023, белого цвета, страница 227, Условие

Высоковольтные ЛЭП постоянного тока позволяют передавать электроэнергию с меньшими потерями, чем ЛЭП переменного тока. Как вы думаете, с чем связано повсеместное применение именно ЛЭП переменного тока?

Решение 1. Это любопытно (с. 227)
Физика, 8 класс Учебник, автор: Пёрышкин И М, издательство Просвещение, Москва, 2023, белого цвета, страница 227, Решение 1
Решение 3. Это любопытно (с. 227)
Физика, 8 класс Учебник, автор: Пёрышкин И М, издательство Просвещение, Москва, 2023, белого цвета, страница 227, Решение 3
Решение 4. Это любопытно (с. 227)

Несмотря на то, что высоковольтные линии электропередачи (ЛЭП) постоянного тока действительно обладают меньшими потерями при передаче на сверхдальние расстояния, повсеместное применение получили ЛЭП переменного тока. Это связано с ключевым преимуществом переменного тока: возможностью легко и с высоким КПД изменять напряжение с помощью трансформаторов.

Рассмотрим процесс передачи электроэнергии от станции до потребителя:

  1. Производство электроэнергии. Электроэнергия на электростанциях вырабатывается генераторами переменного тока при относительно невысоких напряжениях (например, 10–25 кВ).
  2. Передача на большие расстояния. Для эффективной передачи энергии на большие расстояния необходимо минимизировать потери. Потери мощности в проводах определяются законом Джоуля-Ленца: $P_{потерь} = I^2 \cdot R$, где $I$ — сила тока, а $R$ — сопротивление линии. Передаваемая же мощность равна $P = U \cdot I$. Чтобы передать ту же мощность $P$ при меньшей силе тока $I$ (и, следовательно, значительно уменьшить потери), необходимо увеличить напряжение $U$.
  3. Трансформация напряжения. Именно здесь проявляется главное преимущество переменного тока. Трансформаторы, работающие на принципе электромагнитной индукции, позволяют очень эффективно (с КПД более 99%) повышать напряжение перед передачей (например, до 500-750 кВ) и понижать его в несколько этапов перед подачей потребителям (до бытовых 220/380 В). Трансформатор работает только с переменным током, так как для индуцирования ЭДС во вторичной обмотке необходимо переменное магнитное поле, создаваемое переменным током в первичной обмотке.
  4. Сложность систем постоянного тока. Для передачи постоянного тока на высоком напряжении необходимо сначала преобразовать переменный ток от генератора в постоянный с помощью дорогостоящих и сложных выпрямителей. Затем, на приёмном конце линии, постоянный ток нужно снова преобразовать в переменный с помощью инверторов, чтобы его можно было трансформировать до уровней, пригодных для конечных потребителей. Эти преобразователи (выпрямители и инверторы) исторически были и остаются значительно сложнее, дороже и менее надежными, чем простые и надежные трансформаторы.

Таким образом, хотя сами линии постоянного тока экономичнее для очень длинных дистанций (где экономия на потерях перекрывает стоимость преобразователей), для создания разветвлённой сети энергоснабжения, охватывающей города и предприятия с множеством этапов понижения напряжения, система переменного тока оказывается значительно проще и дешевле в реализации и эксплуатации.

Ответ: Повсеместное применение ЛЭП переменного тока связано с тем, что напряжение переменного тока можно легко и эффективно изменять (повышать для передачи и понижать для потребления) с помощью простых, дешевых и надежных устройств — трансформаторов. Это позволяет минимизировать потери энергии в проводах при передаче на большие расстояния и безопасно доставлять ее конечным потребителям. Преобразование же напряжения в сетях постоянного тока требует значительно более сложного и дорогого оборудования.

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