Номер 128, страница 227 - 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. Магнитное поле. 31. Магнитное поле. Вектор магнитной индукции. Олимпиадные задачи - номер 128, страница 227.

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                          #original: array:6 [
                            "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 {#1127
                          #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 {#1128
                      #items: array:1 [
                        0 => App\Models\Term {#1129
                          #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 {#1130
                      #items: array:3 [
                        0 => App\Models\Term {#1131
                          #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 {#1132
                          #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 {#1133
                          #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 {#1134
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1135
                      #items: array:1 [
                        0 => App\Models\Term {#1136
                          #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 {#1137
                      #items: array:1 [
                        0 => App\Models\Term {#1138
                          #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 {#1139
                      #items: array:1 [
                        0 => App\Models\Term {#1140
                          #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 {#1141
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1142
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1143
                      #items: array:1 [
                        0 => App\Models\Term {#1144
                          #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 {#1145
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1146
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1147
                      #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 {#1148
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1149
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1150
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1151
                      #items: array:1 [
                        0 => App\Models\Term {#1152
                          #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 {#1124}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1125}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1128}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1130}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1134}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1135}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1137}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1139}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1141}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1142}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1143}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1145}
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1146}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1147}
                    "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 {#1148}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1149}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1150}
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1151}
                    "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 {#1153
              #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 {#1121}
            "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 {#1155}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1153}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        1 => App\Models\Branch {#1154
          #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" => 1319364
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Магнитное поле"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1156
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "220"
            "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 {#1157
              #items: array:1 [
                0 => App\Models\Book {#1122}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1158
              #items: array:1 [
                0 => App\Models\Branch {#1034}
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1319364
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Магнитное поле"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1156}
            "field_page_start" => "220"
            "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 {#1157}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1158}
          ]
          #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 {#1159
          #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" => 1319365
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "31. Магнитное поле. Вектор магнитной индукции"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1160
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "220"
            "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 {#1161
              #items: array:1 [
                0 => App\Models\Book {#1122}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1170
              #items: array:1 [
                0 => App\Models\Branch {#1169
                  #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" => 1319364
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Магнитное поле"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1171
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "220"
                    "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 {#1172
                      #items: array:1 [
                        0 => App\Models\Book {#1122}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1173
                      #items: array:1 [
                        0 => App\Models\Branch {#1034}
                      ]
                      #escapeWhenCastingToString: false
                    }
                  ]
                  #original: array:24 [
                    "id" => 1319364
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Магнитное поле"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1171}
                    "field_page_start" => "220"
                    "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 {#1172}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1173}
                  ]
                  #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" => 1319365
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "31. Магнитное поле. Вектор магнитной индукции"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1160}
            "field_page_start" => "220"
            "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 {#1161}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1170}
          ]
          #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 {#1163
          #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" => 1319367
            "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 {#1162
              #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 {#1166
              #items: array:1 [
                0 => App\Models\Book {#1122}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1179
              #items: array:1 [
                0 => App\Models\Branch {#1178
                  #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" => 1319365
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "31. Магнитное поле. Вектор магнитной индукции"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1180
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "220"
                    "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 {#1181
                      #items: array:1 [
                        0 => App\Models\Book {#1122}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1182
                      #items: array:1 [
                        0 => App\Models\Branch {#1169}
                      ]
                      #escapeWhenCastingToString: false
                    }
                  ]
                  #original: array:24 [
                    "id" => 1319365
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "31. Магнитное поле. Вектор магнитной индукции"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1180}
                    "field_page_start" => "220"
                    "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 {#1181}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1182}
                  ]
                  #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" => 1319367
            "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 {#1162}
            "field_page_start" => "226"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
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            "text" => "<p><strong>O28.</strong> Металлическую полоску, по которой течет ток $\text{I}$, помещают в однородное магнитное поле с индукцией $\vec{B}$ (см. рисунок). При этом между точками A и C возникает разность потенциалов (эффект Холла). Объясните это явление. Найдите разность потенциалов $U_{AC}$, если $AC = a$, $AD = b$. Концентрация свободных электронов равна n.</p><p>☑ $U_{AC} = IB/(enb).$</p><p><strong><em>Решение.</em></strong> При упорядоченном движении электронов на них действует сила Лоренца, отклоняющая электроны в сторону поверхности $CC_1E_1E$ (см. рисунок). В результате на этой поверхности накапливается отрицательный заряд, а на противоположной — положительный. Это приводит к появлению электрического поля, направленного от A к C. Процесс разделения зарядов продолжается до тех пор, пока сила, действующая на электрон со стороны возникшего электрического поля, не скомпенсирует действие силы Лоренца: $eE = evB$ (здесь $\text{v}$ — скорость упорядоченного движения электронов). Поскольку $U_{AC} = \varphi_A - \varphi_C = Ea$ и $I = envS = envab$, получаем $U_{AC} = IB/(enb).$</p>"
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            "text" => "<p><strong>O28.</strong> Металлическую полоску, по которой течет ток $\text{I}$, помещают в однородное магнитное поле с индукцией $\vec{B}$ (см. рисунок). При этом между точками A и C возникает разность потенциалов (эффект Холла). Объясните это явление. Найдите разность потенциалов $U_{AC}$, если $AC = a$, $AD = b$. Концентрация свободных электронов равна n.</p><p>☑ $U_{AC} = IB/(enb).$</p><p><strong><em>Решение.</em></strong> При упорядоченном движении электронов на них действует сила Лоренца, отклоняющая электроны в сторону поверхности $CC_1E_1E$ (см. рисунок). В результате на этой поверхности накапливается отрицательный заряд, а на противоположной — положительный. Это приводит к появлению электрического поля, направленного от A к C. Процесс разделения зарядов продолжается до тех пор, пока сила, действующая на электрон со стороны возникшего электрического поля, не скомпенсирует действие силы Лоренца: $eE = evB$ (здесь $\text{v}$ — скорость упорядоченного движения электронов). Поскольку $U_{AC} = \varphi_A - \varphi_C = Ea$ и $I = envS = envab$, получаем $U_{AC} = IB/(enb).$</p>"
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            "text" => "<p><strong>Объяснение явления (эффект Холла)</strong></p><p>Когда металлическая полоска с током $I$ помещается в магнитное поле $\vec{B}$, перпендикулярное направлению тока, на носители заряда (в металлах это свободные электроны) начинает действовать сила Лоренца. Направление тока $I$ по определению противоположно направлению упорядоченного движения электронов. Скорость электронов $\vec{v}$ направлена против тока. Сила Лоренца, действующая на каждый электрон, определяется выражением $\vec{F_L} = q(\vec{v} \times \vec{B})$, где заряд электрона $q = -e$.</p><p>Согласно правилу левой руки (для отрицательных зарядов) или правилу векторного произведения, сила Лоренца будет отклонять электроны в сторону грани, содержащей точку C. В результате на этой грани накапливается избыточный отрицательный заряд, а на противоположной грани (содержащей точку A) возникает недостаток электронов, что эквивалентно появлению положительного заряда.</p><p>Это разделение зарядов создает поперечное электрическое поле $\vec{E_H}$, направленное от грани A к грани C. Это поле, в свою очередь, создает электрическую силу $\vec{F_E} = q\vec{E_H} = -e\vec{E_H}$, действующую на электроны в направлении, противоположном силе Лоренца (от C к A). Процесс накопления заряда на гранях продолжается до тех пор, пока электрическая сила не уравновесит силу Лоренца: $F_E = F_L$. В этот момент устанавливается стационарное состояние, и между гранями A и C возникает постоянная разность потенциалов $U_{AC}$, называемая напряжением Холла.</p><p><strong>Ответ:</strong> Явление возникновения поперечной разности потенциалов в проводнике с током, помещенном в магнитное поле, называется эффектом Холла. Оно обусловлено действием силы Лоренца на носители заряда, что приводит к их перераспределению и созданию поперечного электрического поля.</p><p><strong>Нахождение разности потенциалов U_AC</strong></p><p><strong>Дано:</strong><br>Сила тока: $I$<br>Индукция магнитного поля: $B$<br>Расстояние $AC = a$<br>Расстояние $AD = b$<br>Концентрация свободных электронов: $n$<br>Заряд электрона: $e$ (по модулю)</p><p>Все величины заданы в общем виде, предполагается, что они находятся в системе СИ.</p><p><strong>Найти:</strong><br>Разность потенциалов $U_{AC}$</p><p><strong>Решение:</strong><br>В установившемся режиме, когда накопление зарядов на гранях прекращается, сила Лоренца $F_L$, действующая на электроны, уравновешивается силой $F_E$ со стороны возникшего поперечного электрического поля Холла $E_H$.<br>$F_L = F_E$<br>$evB = eE_H$<br>где $v$ - средняя скорость упорядоченного движения (дрейфовая скорость) электронов.<br>Отсюда напряженность холловского поля: $E_H = vB$.<br>Разность потенциалов $U_{AC}$ связана с напряженностью однородного электрического поля $E_H$ и расстоянием $a$ между гранями соотношением:<br>$U_{AC} = E_H \cdot a = vBa$<br>Сила тока $I$ связана с дрейфовой скоростью электронов $v$ формулой:<br>$I = jS = (nev)S$<br>где $S$ - площадь поперечного сечения проводника, перпендикулярного току. В данном случае $S = a \cdot b$.<br>$I = nev(ab)$<br>Выразим дрейфовую скорость $v$ из этой формулы:<br>$v = \frac{I}{neab}$<br>Теперь подставим выражение для скорости $v$ в формулу для разности потенциалов $U_{AC}$:<br>$U_{AC} = \left(\frac{I}{neab}\right)Ba$<br>Сократив $a$, получаем окончательное выражение:<br>$U_{AC} = \frac{IB}{neb}$</p><p><strong>Ответ:</strong> $U_{AC} = \frac{IB}{neb}$</p>"
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            "text" => "<p><strong>Объяснение явления (эффект Холла)</strong></p><p>Когда металлическая полоска с током $I$ помещается в магнитное поле $\vec{B}$, перпендикулярное направлению тока, на носители заряда (в металлах это свободные электроны) начинает действовать сила Лоренца. Направление тока $I$ по определению противоположно направлению упорядоченного движения электронов. Скорость электронов $\vec{v}$ направлена против тока. Сила Лоренца, действующая на каждый электрон, определяется выражением $\vec{F_L} = q(\vec{v} \times \vec{B})$, где заряд электрона $q = -e$.</p><p>Согласно правилу левой руки (для отрицательных зарядов) или правилу векторного произведения, сила Лоренца будет отклонять электроны в сторону грани, содержащей точку C. В результате на этой грани накапливается избыточный отрицательный заряд, а на противоположной грани (содержащей точку A) возникает недостаток электронов, что эквивалентно появлению положительного заряда.</p><p>Это разделение зарядов создает поперечное электрическое поле $\vec{E_H}$, направленное от грани A к грани C. Это поле, в свою очередь, создает электрическую силу $\vec{F_E} = q\vec{E_H} = -e\vec{E_H}$, действующую на электроны в направлении, противоположном силе Лоренца (от C к A). Процесс накопления заряда на гранях продолжается до тех пор, пока электрическая сила не уравновесит силу Лоренца: $F_E = F_L$. В этот момент устанавливается стационарное состояние, и между гранями A и C возникает постоянная разность потенциалов $U_{AC}$, называемая напряжением Холла.</p><p><strong>Ответ:</strong> Явление возникновения поперечной разности потенциалов в проводнике с током, помещенном в магнитное поле, называется эффектом Холла. Оно обусловлено действием силы Лоренца на носители заряда, что приводит к их перераспределению и созданию поперечного электрического поля.</p><p><strong>Нахождение разности потенциалов U_AC</strong></p><p><strong>Дано:</strong><br>Сила тока: $I$<br>Индукция магнитного поля: $B$<br>Расстояние $AC = a$<br>Расстояние $AD = b$<br>Концентрация свободных электронов: $n$<br>Заряд электрона: $e$ (по модулю)</p><p>Все величины заданы в общем виде, предполагается, что они находятся в системе СИ.</p><p><strong>Найти:</strong><br>Разность потенциалов $U_{AC}$</p><p><strong>Решение:</strong><br>В установившемся режиме, когда накопление зарядов на гранях прекращается, сила Лоренца $F_L$, действующая на электроны, уравновешивается силой $F_E$ со стороны возникшего поперечного электрического поля Холла $E_H$.<br>$F_L = F_E$<br>$evB = eE_H$<br>где $v$ - средняя скорость упорядоченного движения (дрейфовая скорость) электронов.<br>Отсюда напряженность холловского поля: $E_H = vB$.<br>Разность потенциалов $U_{AC}$ связана с напряженностью однородного электрического поля $E_H$ и расстоянием $a$ между гранями соотношением:<br>$U_{AC} = E_H \cdot a = vBa$<br>Сила тока $I$ связана с дрейфовой скоростью электронов $v$ формулой:<br>$I = jS = (nev)S$<br>где $S$ - площадь поперечного сечения проводника, перпендикулярного току. В данном случае $S = a \cdot b$.<br>$I = nev(ab)$<br>Выразим дрейфовую скорость $v$ из этой формулы:<br>$v = \frac{I}{neab}$<br>Теперь подставим выражение для скорости $v$ в формулу для разности потенциалов $U_{AC}$:<br>$U_{AC} = \left(\frac{I}{neab}\right)Ba$<br>Сократив $a$, получаем окончательное выражение:<br>$U_{AC} = \frac{IB}{neb}$</p><p><strong>Ответ:</strong> $U_{AC} = \frac{IB}{neb}$</p>"
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№128 (с. 227)
Условие. №128 (с. 227)
скриншот условия
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 227, номер 128, Условие
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 227, номер 128, Условие (продолжение 2)

O28. Металлическую полоску, по которой течет ток $\text{I}$, помещают в однородное магнитное поле с индукцией $\vec{B}$ (см. рисунок). При этом между точками A и C возникает разность потенциалов (эффект Холла). Объясните это явление. Найдите разность потенциалов $U_{AC}$, если $AC = a$, $AD = b$. Концентрация свободных электронов равна n.

☑ $U_{AC} = IB/(enb).$

Решение. При упорядоченном движении электронов на них действует сила Лоренца, отклоняющая электроны в сторону поверхности $CC_1E_1E$ (см. рисунок). В результате на этой поверхности накапливается отрицательный заряд, а на противоположной — положительный. Это приводит к появлению электрического поля, направленного от A к C. Процесс разделения зарядов продолжается до тех пор, пока сила, действующая на электрон со стороны возникшего электрического поля, не скомпенсирует действие силы Лоренца: $eE = evB$ (здесь $\text{v}$ — скорость упорядоченного движения электронов). Поскольку $U_{AC} = \varphi_A - \varphi_C = Ea$ и $I = envS = envab$, получаем $U_{AC} = IB/(enb).$

Решение. №128 (с. 227)

Объяснение явления (эффект Холла)

Когда металлическая полоска с током $I$ помещается в магнитное поле $\vec{B}$, перпендикулярное направлению тока, на носители заряда (в металлах это свободные электроны) начинает действовать сила Лоренца. Направление тока $I$ по определению противоположно направлению упорядоченного движения электронов. Скорость электронов $\vec{v}$ направлена против тока. Сила Лоренца, действующая на каждый электрон, определяется выражением $\vec{F_L} = q(\vec{v} \times \vec{B})$, где заряд электрона $q = -e$.

Согласно правилу левой руки (для отрицательных зарядов) или правилу векторного произведения, сила Лоренца будет отклонять электроны в сторону грани, содержащей точку C. В результате на этой грани накапливается избыточный отрицательный заряд, а на противоположной грани (содержащей точку A) возникает недостаток электронов, что эквивалентно появлению положительного заряда.

Это разделение зарядов создает поперечное электрическое поле $\vec{E_H}$, направленное от грани A к грани C. Это поле, в свою очередь, создает электрическую силу $\vec{F_E} = q\vec{E_H} = -e\vec{E_H}$, действующую на электроны в направлении, противоположном силе Лоренца (от C к A). Процесс накопления заряда на гранях продолжается до тех пор, пока электрическая сила не уравновесит силу Лоренца: $F_E = F_L$. В этот момент устанавливается стационарное состояние, и между гранями A и C возникает постоянная разность потенциалов $U_{AC}$, называемая напряжением Холла.

Ответ: Явление возникновения поперечной разности потенциалов в проводнике с током, помещенном в магнитное поле, называется эффектом Холла. Оно обусловлено действием силы Лоренца на носители заряда, что приводит к их перераспределению и созданию поперечного электрического поля.

Нахождение разности потенциалов U_AC

Дано:
Сила тока: $I$
Индукция магнитного поля: $B$
Расстояние $AC = a$
Расстояние $AD = b$
Концентрация свободных электронов: $n$
Заряд электрона: $e$ (по модулю)

Все величины заданы в общем виде, предполагается, что они находятся в системе СИ.

Найти:
Разность потенциалов $U_{AC}$

Решение:
В установившемся режиме, когда накопление зарядов на гранях прекращается, сила Лоренца $F_L$, действующая на электроны, уравновешивается силой $F_E$ со стороны возникшего поперечного электрического поля Холла $E_H$.
$F_L = F_E$
$evB = eE_H$
где $v$ - средняя скорость упорядоченного движения (дрейфовая скорость) электронов.
Отсюда напряженность холловского поля: $E_H = vB$.
Разность потенциалов $U_{AC}$ связана с напряженностью однородного электрического поля $E_H$ и расстоянием $a$ между гранями соотношением:
$U_{AC} = E_H \cdot a = vBa$
Сила тока $I$ связана с дрейфовой скоростью электронов $v$ формулой:
$I = jS = (nev)S$
где $S$ - площадь поперечного сечения проводника, перпендикулярного току. В данном случае $S = a \cdot b$.
$I = nev(ab)$
Выразим дрейфовую скорость $v$ из этой формулы:
$v = \frac{I}{neab}$
Теперь подставим выражение для скорости $v$ в формулу для разности потенциалов $U_{AC}$:
$U_{AC} = \left(\frac{I}{neab}\right)Ba$
Сократив $a$, получаем окончательное выражение:
$U_{AC} = \frac{IB}{neb}$

Ответ: $U_{AC} = \frac{IB}{neb}$

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