Номер 115, страница 203 - 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. 28. Электродвижущая сила. Закон Ома для полной цепи. Олимпиадные задачи - номер 115, страница 203.

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                            "id" => 5459
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "10"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "десятый"
                              "field_creative_case" => "десятым"
                              "field_dative_case" => "десятому"
                              "field_genitive_case" => "десятого"
                              "field_nominative_case" => "десятый"
                              "field_prepositional_case" => "десятом"
                            ]
                            "field_translit" => "desjatyj"
                          ]
                          #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\Term {#1166
                          #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" => 5460
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "11"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "одиннадцатый"
                              "field_creative_case" => "одиннадцатым"
                              "field_dative_case" => "одиннадцатому"
                              "field_genitive_case" => "одинадцатого"
                              "field_nominative_case" => "одинадцатый"
                              "field_prepositional_case" => "одиннадцатом"
                            ]
                            "field_translit" => "odinadcatyj"
                          ]
                          #original: array:6 [
                            "id" => 5460
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "11"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "одиннадцатый"
                              "field_creative_case" => "одиннадцатым"
                              "field_dative_case" => "одиннадцатому"
                              "field_genitive_case" => "одинадцатого"
                              "field_nominative_case" => "одинадцатый"
                              "field_prepositional_case" => "одиннадцатом"
                            ]
                            "field_translit" => "odinadcatyj"
                          ]
                          #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_publisher" => Illuminate\Database\Eloquent\Collection {#1167
                      #items: array:1 [
                        0 => App\Models\Term {#1168
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 5158
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Илекса"
                            "field_cases" => null
                            "field_translit" => "ileksa"
                          ]
                          #original: array:6 [
                            "id" => 5158
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Илекса"
                            "field_cases" => null
                            "field_translit" => "ileksa"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1169
                      #items: array:3 [
                        0 => App\Models\Term {#1170
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [
                            "id" => 4102
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Гельфгат"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Илья"
                            "field_patronymic" => "Маркович"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 4102
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Гельфгат"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Илья"
                            "field_patronymic" => "Маркович"
                            "field_surname_rp" => null
                          ]
                          #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\Term {#1171
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [
                            "id" => 4104
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Генденштейн"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Лев"
                            "field_patronymic" => "Элевич"
                            "field_surname_rp" => "Генденштейна"
                          ]
                          #original: array:12 [
                            "id" => 4104
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Генденштейн"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Лев"
                            "field_patronymic" => "Элевич"
                            "field_surname_rp" => "Генденштейна"
                          ]
                          #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\Term {#1172
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [
                            "id" => 4583
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Кирик"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Леонид"
                            "field_patronymic" => "Анатольевич"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 4583
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Кирик"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Леонид"
                            "field_patronymic" => "Анатольевич"
                            "field_surname_rp" => null
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1173
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1174
                      #items: array:1 [
                        0 => App\Models\Term {#1175
                          #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" => 6518
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Задачник"
                            "field_book_type_foreign" => null
                            "field_cases" => array:6 [
                              "field_accusative_case" => "задачник"
                              "field_creative_case" => "задачником"
                              "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"
                          ]
                          #original: array:10 [
                            "id" => 6518
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Задачник"
                            "field_book_type_foreign" => null
                            "field_cases" => array:6 [
                              "field_accusative_case" => "задачник"
                              "field_creative_case" => "задачником"
                              "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 {#1176
                      #items: array:1 [
                        0 => App\Models\Term {#1177
                          #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 {#1178
                      #items: array:1 [
                        0 => App\Models\Term {#1179
                          #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 {#1180
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1181
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1182
                      #items: array:1 [
                        0 => App\Models\Term {#1183
                          #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 {#1184
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1185
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1186
                      #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 {#1187
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1188
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1189
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1190
                      #items: array:1 [
                        0 => App\Models\Term {#1191
                          #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 {#1163}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1164}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1167}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1169}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1173}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1174}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1176}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1178}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1180}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1181}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1182}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1184}
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1185}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1186}
                    "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 {#1187}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1188}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1189}
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1190}
                    "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 {#1192
              #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 {#1160}
            "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 {#1194}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1192}
          ]
          #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 {#1193
          #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 {#1195
              #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 {#1196
              #items: array:1 [
                0 => App\Models\Book {#1161}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1197
              #items: array:1 [
                0 => App\Models\Branch {#1034}
              ]
              #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 {#1195}
            "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 {#1196}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1197}
          ]
          #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 {#1198
          #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" => 1319355
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "28. Электродвижущая сила. Закон Ома для полной цепи"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1199
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "200"
            "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 {#1200
              #items: array:1 [
                0 => App\Models\Book {#1161}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1242
              #items: array:1 [
                0 => App\Models\Branch {#1201
                  #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 {#1203
                      #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 {#1202
                      #items: array:1 [
                        0 => App\Models\Book {#1204 …30}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1235
                      #items: array:1 [
                        0 => App\Models\Branch {#1236 …30}
                      ]
                      #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 {#1203}
                    "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 {#1202}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1235}
                  ]
                  #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" => 1319355
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "28. Электродвижущая сила. Закон Ома для полной цепи"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1199}
            "field_page_start" => "200"
            "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 {#1200}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1242}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        3 => App\Models\Branch {#1240
          #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" => 1319357
            "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 {#1241
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "203"
            "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 {#1243
              #items: array:1 [
                0 => App\Models\Book {#1161}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1252
              #items: array:1 [
                0 => App\Models\Branch {#1251
                  #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" => 1319355
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "28. Электродвижущая сила. Закон Ома для полной цепи"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1253
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "200"
                    "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 {#1254
                      #items: array:1 [
                        0 => App\Models\Book {#1161}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1255
                      #items: array:1 [
                        0 => App\Models\Branch {#1201}
                      ]
                      #escapeWhenCastingToString: false
                    }
                  ]
                  #original: array:24 [
                    "id" => 1319355
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "28. Электродвижущая сила. Закон Ома для полной цепи"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1253}
                    "field_page_start" => "200"
                    "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 {#1254}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1255}
                  ]
                  #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" => 1319357
            "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 {#1241}
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            "text" => "<p><strong>O15.</strong> Два источника ЭДС соединены, как показано на рисунке. Найдите разность потенциалов между точками А и В. Какой станет разность потенциалов, если изменить полярность включения второго источника?</p><p>☑ $\frac{\mathcal{E}_1 r_2 + \mathcal{E}_2 r_1}{r_1+r_2}$, $\frac{\mathcal{E}_1 r_2 - \mathcal{E}_2 r_1}{r_1+r_2}$</p><p><strong>Решение.</strong> Ток в цепи идет против часовой стрелки. Сила тока $I = \frac{\mathcal{E}_1 + \mathcal{E}_2}{r_1+r_2}$. Искомая разность потенциалов между точками А и В: $\mathcal{E}_1 - I r_1 = \frac{\mathcal{E}_1 r_2 - \mathcal{E}_2 r_1}{r_1+r_2}$; обратим внимание, что она равна нулю при $\mathcal{E}_1/r_1 = \mathcal{E}_2/r_2$, т. е. когда у обоих источников одинаковы токи короткого замыкания. Если изменить полярность второго источника, в выражении для разности потенциалов знак перед $\mathcal{E}_2$ тоже изменится, и в результате получим $\frac{\mathcal{E}_1 r_2 + \mathcal{E}_2 r_1}{r_1+r_2}$. Если $\mathcal{E}_1 = \mathcal{E}_2$, искомая разность потенциалов равна ЭДС любого из источников.</p>"
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            "text" => "<p><strong>O15.</strong> Два источника ЭДС соединены, как показано на рисунке. Найдите разность потенциалов между точками А и В. Какой станет разность потенциалов, если изменить полярность включения второго источника?</p><p>☑ $\frac{\mathcal{E}_1 r_2 + \mathcal{E}_2 r_1}{r_1+r_2}$, $\frac{\mathcal{E}_1 r_2 - \mathcal{E}_2 r_1}{r_1+r_2}$</p><p><strong>Решение.</strong> Ток в цепи идет против часовой стрелки. Сила тока $I = \frac{\mathcal{E}_1 + \mathcal{E}_2}{r_1+r_2}$. Искомая разность потенциалов между точками А и В: $\mathcal{E}_1 - I r_1 = \frac{\mathcal{E}_1 r_2 - \mathcal{E}_2 r_1}{r_1+r_2}$; обратим внимание, что она равна нулю при $\mathcal{E}_1/r_1 = \mathcal{E}_2/r_2$, т. е. когда у обоих источников одинаковы токи короткого замыкания. Если изменить полярность второго источника, в выражении для разности потенциалов знак перед $\mathcal{E}_2$ тоже изменится, и в результате получим $\frac{\mathcal{E}_1 r_2 + \mathcal{E}_2 r_1}{r_1+r_2}$. Если $\mathcal{E}_1 = \mathcal{E}_2$, искомая разность потенциалов равна ЭДС любого из источников.</p>"
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            "text" => "<p><strong>Дано:</strong></p><p>ЭДС первого источника: $E_1$</p><p>Внутреннее сопротивление первого источника: $r_1$</p><p>ЭДС второго источника: $E_2$</p><p>Внутреннее сопротивление второго источника: $r_2$</p><p><em>Примечание: Хотя на схеме источники изображены со встречным включением, решение в задачнике предполагает, что они включены согласно. Будем следовать этому предположению для получения ответа, приведенного в задачнике.</em></p><p><strong>Найти:</strong></p><p><strong>1.</strong> Разность потенциалов $U_{AB} = \phi_A - \phi_B$ в исходной (согласной) схеме.</p><p><strong>2.</strong> Разность потенциалов $U'_{AB} = \phi_A - \phi_B$ при изменении полярности второго источника (встречное включение).</p><p><strong>Решение:</strong></p><p><strong>1.</strong> Найдите разность потенциалов между точками А и В.</p><p>При согласном включении источников их ЭДС складываются. Цепь представляет собой один замкнутый контур. Ток в контуре будет течь против часовой стрелки.</p><p>Согласно закону Ома для полной цепи, сила тока $I$ равна отношению суммарной ЭДС к суммарному сопротивлению:</p><p>$I = \frac{E_1 + E_2}{r_1 + r_2}$</p><p>Разность потенциалов между точками А и В ($U_{AB} = \phi_A - \phi_B$) найдем, рассмотрев путь от точки B до точки A через верхнюю ветвь цепи. Двигаясь от B к A, мы проходим источник $E_1$ от отрицательного полюса к положительному (потенциал увеличивается на $E_1$) и сопротивление $r_1$ по направлению тока (потенциал уменьшается на $I r_1$).</p><p>Таким образом, потенциал в точке A выражается через потенциал в точке B как:</p><p>$\phi_A = \phi_B + E_1 - I \cdot r_1$</p><p>Отсюда искомая разность потенциалов:</p><p>$U_{AB} = \phi_A - \phi_B = E_1 - I \cdot r_1$</p><p>Подставим в это выражение найденную силу тока $I$:</p><p>$U_{AB} = E_1 - \left(\frac{E_1 + E_2}{r_1 + r_2}\right) r_1$</p><p>Приведем к общему знаменателю и упростим:</p><p>$U_{AB} = \frac{E_1(r_1 + r_2) - (E_1 + E_2)r_1}{r_1 + r_2} = \frac{E_1 r_1 + E_1 r_2 - E_1 r_1 - E_2 r_1}{r_1 + r_2} = \frac{E_1 r_2 - E_2 r_1}{r_1 + r_2}$</p><p><strong>Ответ:</strong> Разность потенциалов между точками А и В равна $\frac{E_1 r_2 - E_2 r_1}{r_1 + r_2}$.</p><p><strong>2.</strong> Какой станет разность потенциалов, если изменить полярность включения второго источника?</p><p>Если изменить полярность второго источника $E_2$, то источники окажутся включенными встречно. Их суммарная ЭДС будет равна разности $|E_1 - E_2|$. Предположим для определенности, что $E_1 &gt; E_2$, тогда ток $I'$ будет течь по часовой стрелке.</p><p>Сила тока в новой цепи:</p><p>$I' = \frac{E_1 - E_2}{r_1 + r_2}$</p><p>Снова найдем разность потенциалов $U'_{AB} = \phi_A - \phi_B$, двигаясь от B к A через верхнюю ветвь. В этот раз мы движемся против направления тока $I'$.</p><p>При движении от B к A мы проходим источник $E_1$ от отрицательного полюса к положительному (потенциал увеличивается на $E_1$) и сопротивление $r_1$ против направления тока (потенциал также увеличивается на $I' r_1$).</p><p>$\phi_A = \phi_B + E_1 + I' \cdot r_1$</p><p>Новая разность потенциалов:</p><p>$U'_{AB} = \phi_A - \phi_B = E_1 + I' \cdot r_1$</p><p>Подставим выражение для силы тока $I'$:</p><p>$U'_{AB} = E_1 + \left(\frac{E_1 - E_2}{r_1 + r_2}\right) r_1$</p><p>Приведем к общему знаменателю и упростим:</p><p>$U'_{AB} = \frac{E_1(r_1 + r_2) + (E_1 - E_2)r_1}{r_1 + r_2} = \frac{E_1 r_1 + E_1 r_2 + E_1 r_1 - E_2 r_1}{r_1 + r_2} = \frac{E_1 r_2 + E_2 r_1}{r_1 + r_2}$</p><p><em>(Примечание: результат не изменится, если предположить, что $E_2 &gt; E_1$. В этом случае ток потечет в обратную сторону, и знаки в расчете изменятся соответствующим образом, приведя к тому же конечному ответу).</em></p><p><strong>Ответ:</strong> Разность потенциалов станет равной $\frac{E_1 r_2 + E_2 r_1}{r_1 + r_2}$.</p>"
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            "text" => "<p><strong>Дано:</strong></p><p>ЭДС первого источника: $E_1$</p><p>Внутреннее сопротивление первого источника: $r_1$</p><p>ЭДС второго источника: $E_2$</p><p>Внутреннее сопротивление второго источника: $r_2$</p><p><em>Примечание: Хотя на схеме источники изображены со встречным включением, решение в задачнике предполагает, что они включены согласно. Будем следовать этому предположению для получения ответа, приведенного в задачнике.</em></p><p><strong>Найти:</strong></p><p><strong>1.</strong> Разность потенциалов $U_{AB} = \phi_A - \phi_B$ в исходной (согласной) схеме.</p><p><strong>2.</strong> Разность потенциалов $U'_{AB} = \phi_A - \phi_B$ при изменении полярности второго источника (встречное включение).</p><p><strong>Решение:</strong></p><p><strong>1.</strong> Найдите разность потенциалов между точками А и В.</p><p>При согласном включении источников их ЭДС складываются. Цепь представляет собой один замкнутый контур. Ток в контуре будет течь против часовой стрелки.</p><p>Согласно закону Ома для полной цепи, сила тока $I$ равна отношению суммарной ЭДС к суммарному сопротивлению:</p><p>$I = \frac{E_1 + E_2}{r_1 + r_2}$</p><p>Разность потенциалов между точками А и В ($U_{AB} = \phi_A - \phi_B$) найдем, рассмотрев путь от точки B до точки A через верхнюю ветвь цепи. Двигаясь от B к A, мы проходим источник $E_1$ от отрицательного полюса к положительному (потенциал увеличивается на $E_1$) и сопротивление $r_1$ по направлению тока (потенциал уменьшается на $I r_1$).</p><p>Таким образом, потенциал в точке A выражается через потенциал в точке B как:</p><p>$\phi_A = \phi_B + E_1 - I \cdot r_1$</p><p>Отсюда искомая разность потенциалов:</p><p>$U_{AB} = \phi_A - \phi_B = E_1 - I \cdot r_1$</p><p>Подставим в это выражение найденную силу тока $I$:</p><p>$U_{AB} = E_1 - \left(\frac{E_1 + E_2}{r_1 + r_2}\right) r_1$</p><p>Приведем к общему знаменателю и упростим:</p><p>$U_{AB} = \frac{E_1(r_1 + r_2) - (E_1 + E_2)r_1}{r_1 + r_2} = \frac{E_1 r_1 + E_1 r_2 - E_1 r_1 - E_2 r_1}{r_1 + r_2} = \frac{E_1 r_2 - E_2 r_1}{r_1 + r_2}$</p><p><strong>Ответ:</strong> Разность потенциалов между точками А и В равна $\frac{E_1 r_2 - E_2 r_1}{r_1 + r_2}$.</p><p><strong>2.</strong> Какой станет разность потенциалов, если изменить полярность включения второго источника?</p><p>Если изменить полярность второго источника $E_2$, то источники окажутся включенными встречно. Их суммарная ЭДС будет равна разности $|E_1 - E_2|$. Предположим для определенности, что $E_1 &gt; E_2$, тогда ток $I'$ будет течь по часовой стрелке.</p><p>Сила тока в новой цепи:</p><p>$I' = \frac{E_1 - E_2}{r_1 + r_2}$</p><p>Снова найдем разность потенциалов $U'_{AB} = \phi_A - \phi_B$, двигаясь от B к A через верхнюю ветвь. В этот раз мы движемся против направления тока $I'$.</p><p>При движении от B к A мы проходим источник $E_1$ от отрицательного полюса к положительному (потенциал увеличивается на $E_1$) и сопротивление $r_1$ против направления тока (потенциал также увеличивается на $I' r_1$).</p><p>$\phi_A = \phi_B + E_1 + I' \cdot r_1$</p><p>Новая разность потенциалов:</p><p>$U'_{AB} = \phi_A - \phi_B = E_1 + I' \cdot r_1$</p><p>Подставим выражение для силы тока $I'$:</p><p>$U'_{AB} = E_1 + \left(\frac{E_1 - E_2}{r_1 + r_2}\right) r_1$</p><p>Приведем к общему знаменателю и упростим:</p><p>$U'_{AB} = \frac{E_1(r_1 + r_2) + (E_1 - E_2)r_1}{r_1 + r_2} = \frac{E_1 r_1 + E_1 r_2 + E_1 r_1 - E_2 r_1}{r_1 + r_2} = \frac{E_1 r_2 + E_2 r_1}{r_1 + r_2}$</p><p><em>(Примечание: результат не изменится, если предположить, что $E_2 &gt; E_1$. В этом случае ток потечет в обратную сторону, и знаки в расчете изменятся соответствующим образом, приведя к тому же конечному ответу).</em></p><p><strong>Ответ:</strong> Разность потенциалов станет равной $\frac{E_1 r_2 + E_2 r_1}{r_1 + r_2}$.</p>"
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№115 (с. 203)
Условие. №115 (с. 203)
скриншот условия
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 203, номер 115, Условие
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 203, номер 115, Условие (продолжение 2)

O15. Два источника ЭДС соединены, как показано на рисунке. Найдите разность потенциалов между точками А и В. Какой станет разность потенциалов, если изменить полярность включения второго источника?

☑ $\frac{\mathcal{E}_1 r_2 + \mathcal{E}_2 r_1}{r_1+r_2}$, $\frac{\mathcal{E}_1 r_2 - \mathcal{E}_2 r_1}{r_1+r_2}$

Решение. Ток в цепи идет против часовой стрелки. Сила тока $I = \frac{\mathcal{E}_1 + \mathcal{E}_2}{r_1+r_2}$. Искомая разность потенциалов между точками А и В: $\mathcal{E}_1 - I r_1 = \frac{\mathcal{E}_1 r_2 - \mathcal{E}_2 r_1}{r_1+r_2}$; обратим внимание, что она равна нулю при $\mathcal{E}_1/r_1 = \mathcal{E}_2/r_2$, т. е. когда у обоих источников одинаковы токи короткого замыкания. Если изменить полярность второго источника, в выражении для разности потенциалов знак перед $\mathcal{E}_2$ тоже изменится, и в результате получим $\frac{\mathcal{E}_1 r_2 + \mathcal{E}_2 r_1}{r_1+r_2}$. Если $\mathcal{E}_1 = \mathcal{E}_2$, искомая разность потенциалов равна ЭДС любого из источников.

Решение. №115 (с. 203)

Дано:

ЭДС первого источника: $E_1$

Внутреннее сопротивление первого источника: $r_1$

ЭДС второго источника: $E_2$

Внутреннее сопротивление второго источника: $r_2$

Примечание: Хотя на схеме источники изображены со встречным включением, решение в задачнике предполагает, что они включены согласно. Будем следовать этому предположению для получения ответа, приведенного в задачнике.

Найти:

1. Разность потенциалов $U_{AB} = \phi_A - \phi_B$ в исходной (согласной) схеме.

2. Разность потенциалов $U'_{AB} = \phi_A - \phi_B$ при изменении полярности второго источника (встречное включение).

Решение:

1. Найдите разность потенциалов между точками А и В.

При согласном включении источников их ЭДС складываются. Цепь представляет собой один замкнутый контур. Ток в контуре будет течь против часовой стрелки.

Согласно закону Ома для полной цепи, сила тока $I$ равна отношению суммарной ЭДС к суммарному сопротивлению:

$I = \frac{E_1 + E_2}{r_1 + r_2}$

Разность потенциалов между точками А и В ($U_{AB} = \phi_A - \phi_B$) найдем, рассмотрев путь от точки B до точки A через верхнюю ветвь цепи. Двигаясь от B к A, мы проходим источник $E_1$ от отрицательного полюса к положительному (потенциал увеличивается на $E_1$) и сопротивление $r_1$ по направлению тока (потенциал уменьшается на $I r_1$).

Таким образом, потенциал в точке A выражается через потенциал в точке B как:

$\phi_A = \phi_B + E_1 - I \cdot r_1$

Отсюда искомая разность потенциалов:

$U_{AB} = \phi_A - \phi_B = E_1 - I \cdot r_1$

Подставим в это выражение найденную силу тока $I$:

$U_{AB} = E_1 - \left(\frac{E_1 + E_2}{r_1 + r_2}\right) r_1$

Приведем к общему знаменателю и упростим:

$U_{AB} = \frac{E_1(r_1 + r_2) - (E_1 + E_2)r_1}{r_1 + r_2} = \frac{E_1 r_1 + E_1 r_2 - E_1 r_1 - E_2 r_1}{r_1 + r_2} = \frac{E_1 r_2 - E_2 r_1}{r_1 + r_2}$

Ответ: Разность потенциалов между точками А и В равна $\frac{E_1 r_2 - E_2 r_1}{r_1 + r_2}$.

2. Какой станет разность потенциалов, если изменить полярность включения второго источника?

Если изменить полярность второго источника $E_2$, то источники окажутся включенными встречно. Их суммарная ЭДС будет равна разности $|E_1 - E_2|$. Предположим для определенности, что $E_1 > E_2$, тогда ток $I'$ будет течь по часовой стрелке.

Сила тока в новой цепи:

$I' = \frac{E_1 - E_2}{r_1 + r_2}$

Снова найдем разность потенциалов $U'_{AB} = \phi_A - \phi_B$, двигаясь от B к A через верхнюю ветвь. В этот раз мы движемся против направления тока $I'$.

При движении от B к A мы проходим источник $E_1$ от отрицательного полюса к положительному (потенциал увеличивается на $E_1$) и сопротивление $r_1$ против направления тока (потенциал также увеличивается на $I' r_1$).

$\phi_A = \phi_B + E_1 + I' \cdot r_1$

Новая разность потенциалов:

$U'_{AB} = \phi_A - \phi_B = E_1 + I' \cdot r_1$

Подставим выражение для силы тока $I'$:

$U'_{AB} = E_1 + \left(\frac{E_1 - E_2}{r_1 + r_2}\right) r_1$

Приведем к общему знаменателю и упростим:

$U'_{AB} = \frac{E_1(r_1 + r_2) + (E_1 - E_2)r_1}{r_1 + r_2} = \frac{E_1 r_1 + E_1 r_2 + E_1 r_1 - E_2 r_1}{r_1 + r_2} = \frac{E_1 r_2 + E_2 r_1}{r_1 + r_2}$

(Примечание: результат не изменится, если предположить, что $E_2 > E_1$. В этом случае ток потечет в обратную сторону, и знаки в расчете изменятся соответствующим образом, приведя к тому же конечному ответу).

Ответ: Разность потенциалов станет равной $\frac{E_1 r_2 + E_2 r_1}{r_1 + r_2}$.

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