Номер 4, страница 265 - гдз по физике 10 класс учебник часть 1 Генденштейн, Дик

Физика, 10 класс Учебник, авторы: Генденштейн Лев Элевич, Дик Юрий Иванович, издательство Мнемозина, Москва, 2009

Авторы: Генденштейн Л. Э., Дик Ю. И.

Тип: Учебник

Издательство: Мнемозина

Год издания: 2009 - 2026

Уровень обучения: базовый

Часть: 1, 2

ISBN: 978-5-346-03674-6

Молекулярная физика и термодинамика. Глава 6. Термодинамика. Параграф 32. Тепловые двигатели, холодильники и кондиционеры - номер 4, страница 265.

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                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "breadcrumbs" => array:3 [ …3]
                  ]
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                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
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                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1096
              #items: array:1 [
                0 => App\Models\Branch {#1097
                  #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" => 1404532
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Молекулярная физика и термодинамика"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1098 …2}
                    "field_page_start" => "193"
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                    "field_display_branch_in_title" => "1"
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                    "field_display_branch_page" => "1"
                    "field_branch_title_in_content" => "0"
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                    "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 {#1099 …2}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1100 …2}
                  ]
                  #original: array:24 [
                    "id" => 1404532
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Молекулярная физика и термодинамика"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1098 …2}
                    "field_page_start" => "193"
                    "field_branch_display" => "0"
                    "field_branch_expanded" => "0"
                    "field_display_branch_in_title" => "1"
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                    "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 {#1099 …2}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1100 …2}
                  ]
                  #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" => 1404542
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Термодинамика"
            "field_branch_order" => "6"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1064}
            "field_page_start" => "250"
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            "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 {#1066}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1096}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
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          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        2 => App\Models\Branch {#1101
          #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" => 1404544
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Тепловые двигатели, холодильники и кондиционеры"
            "field_branch_order" => "32"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1102
              #items: array:1 [
                0 => App\Models\Term {#1103
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:7 [
                    "id" => 32
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Параграф"
                    "field_cases" => array:6 [ …6]
                    "field_page_check_not_needed" => null
                    "field_short_name" => "§"
                  ]
                  #original: array:7 [
                    "id" => 32
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Параграф"
                    "field_cases" => array:6 [ …6]
                    "field_page_check_not_needed" => null
                    "field_short_name" => "§"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
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                  #touches: []
                  +timestamps: true
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                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "259"
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            "field_display_branch_in_title" => "1"
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            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
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            "field_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 {#1104
              #items: array:1 [
                0 => App\Models\Book {#1105
                  #connection: "mysql"
                  #table: "books"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:50 [
                    "id" => 1937
                    "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 {#1106 …2}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1108 …2}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1110 …2}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1112 …2}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1115 …2}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1116 …2}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1118 …2}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1120 …2}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1122 …2}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1123 …2}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1124 …2}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1126 …2}
                    "field_publication_number" => "7"
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1127 …2}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1129 …2}
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => null
                    "field_publication_year" => "2009"
                    "field_publication_year_until" => null
                    "field_part" => "1, 2"
                    "field_part_writing" => "Часть"
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебник для общеобразовательных организаций"
                    "field_allowed" => null
                    "field_reserve_field" => null
                    "field_link_to_source" => null
                    "field_tasks_count" => "740"
                    "field_priority" => null
                    "field_default_folder" => "/fizika_10/gendenshtejn-u-09/"
                    "field_isbn" => "978-5-346-03674-6"
                    "field_cover" => array:1 [ …1]
                    "field_cover_alts" => array:1 [ …1]
                    "field_covers" => array:1 [ …1]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1130 …2}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1131 …2}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1132 …2}
                    "field_url" => "/10-klass/fizika/gendenshtejn-uchebnik-2009"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1133 …2}
                    "field_metatags_title" => null
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                    "field_h1" => null
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                    "breadcrumbs" => array:3 [ …3]
                  ]
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                    "id" => 1937
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                    "field_subject" => Illuminate\Database\Eloquent\Collection {#1106 …2}
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                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1110 …2}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1112 …2}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1115 …2}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1116 …2}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1118 …2}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1120 …2}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1122 …2}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1123 …2}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1124 …2}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1126 …2}
                    "field_publication_number" => "7"
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1127 …2}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1129 …2}
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => null
                    "field_publication_year" => "2009"
                    "field_publication_year_until" => null
                    "field_part" => "1, 2"
                    "field_part_writing" => "Часть"
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебник для общеобразовательных организаций"
                    "field_allowed" => null
                    "field_reserve_field" => null
                    "field_link_to_source" => null
                    "field_tasks_count" => "740"
                    "field_priority" => null
                    "field_default_folder" => "/fizika_10/gendenshtejn-u-09/"
                    "field_isbn" => "978-5-346-03674-6"
                    "field_cover" => array:1 [ …1]
                    "field_cover_alts" => array:1 [ …1]
                    "field_covers" => array:1 [ …1]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1130 …2}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1131 …2}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1132 …2}
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                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1133 …2}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "breadcrumbs" => array:3 [ …3]
                  ]
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                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1134
              #items: array:1 [
                0 => App\Models\Branch {#1135
                  #connection: "mysql"
                  #table: "branches"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
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                  #perPage: 15
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                  #attributes: array:24 [
                    "id" => 1404542
                    "created_at" => "2026-04-10 13:58:26"
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                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1136 …2}
                    "field_page_start" => "250"
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                    "field_branch_covers" => []
                    "book" => Illuminate\Database\Eloquent\Collection {#1138 …2}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1139 …2}
                  ]
                  #original: array:24 [
                    "id" => 1404542
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Термодинамика"
                    "field_branch_order" => "6"
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1136 …2}
                    "field_page_start" => "250"
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                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "field_branch_cover" => []
                    "field_branch_covers" => []
                    "book" => Illuminate\Database\Eloquent\Collection {#1138 …2}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1139 …2}
                  ]
                  #changes: []
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                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
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                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1404544
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Тепловые двигатели, холодильники и кондиционеры"
            "field_branch_order" => "32"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1102}
            "field_page_start" => "259"
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            "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 {#1104}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1134}
          ]
          #changes: []
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          #attributeCastCache: []
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          #touches: []
          +timestamps: true
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          #hidden: []
          #visible: []
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          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "content" => Illuminate\Database\Eloquent\Collection {#1144
      #items: array:2 [
        0 => App\Models\Element {#1145
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:7 [
            "id" => 1649655
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1146
              #items: array:1 [
                0 => App\Models\Edition {#1147
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:21 [
                    "id" => 5864
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Условие"
                    "field_order" => "1"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1148 …2}
                    "field_content_type" => "free"
                    "field_content_mode" => "text, image"
                    "field_page_content_mode" => "image"
                    "field_content_text_checked" => null
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Автор"
                    "field_moderator" => "stas"
                    "field_edition_type" => "statement"
                    "field_root_dir" => "0-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1150 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1151 …2}
                    "field_process_formula" => "katex"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1152 …2}
                    "field_content_source" => null
                  ]
                  #original: array:21 [
                    "id" => 5864
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Условие"
                    "field_order" => "1"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1148 …2}
                    "field_content_type" => "free"
                    "field_content_mode" => "text, image"
                    "field_page_content_mode" => "image"
                    "field_content_text_checked" => null
                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Автор"
                    "field_moderator" => "stas"
                    "field_edition_type" => "statement"
                    "field_root_dir" => "0-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1150 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1151 …2}
                    "field_process_formula" => "katex"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1152 …2}
                    "field_content_source" => null
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
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            "text" => "<p><strong>Коэффициент полезного действия (КПД) теплового двигателя</strong> — это физическая величина, характеризующая эффективность преобразования тепловой энергии, полученной от нагревателя, в полезную механическую работу. КПД, обозначаемый греческой буквой $\eta$ (эта), является безразмерной величиной и часто выражается в процентах.</p><p>Любой тепловой двигатель работает циклически и для его работы необходимы:</p><p><strong>1.</strong> <em>Нагреватель</em> — источник тепловой энергии с высокой температурой $T_1$, от которого рабочее тело (например, газ или пар) получает количество теплоты $Q_1$.</p><p><strong>2.</strong> <em>Рабочее тело</em> — вещество, которое совершает механическую работу при расширении.</p><p><strong>3.</strong> <em>Холодильник</em> — объект с низкой температурой $T_2$, которому рабочее тело отдает некоторое количество теплоты $Q_2$, не преобразованное в работу.</p><p>За один цикл работы двигатель совершает полезную работу $A_{полезная}$, которая, согласно закону сохранения энергии (первому началу термодинамики), равна разности между количеством теплоты, полученным от нагревателя, и количеством теплоты, отданным холодильнику:$A_{полезная} = Q_1 - Q_2$.</p><p>По определению, КПД равен отношению полезной работы, совершенной двигателем, к количеству теплоты, полученному от нагревателя:$\eta = \frac{A_{полезная}}{Q_1}$.</p><p>Подставив выражение для работы, получим основную формулу для КПД реального теплового двигателя:$\eta = \frac{Q_1 - Q_2}{Q_1} = 1 - \frac{Q_2}{Q_1}$.</p><p>Из второго закона термодинамики следует, что невозможно создать тепловой двигатель, который бы полностью преобразовывал всю полученную теплоту в работу. Это означает, что всегда есть тепловые потери, и часть энергии ($Q_2$) неизбежно передается холодильнику. Следовательно, $Q_2 &gt; 0$, а значит, КПД любого реального теплового двигателя всегда меньше 1 (или 100%).</p><p>Французский инженер Сади Карно в 1824 году определил максимально возможный КПД для теплового двигателя, работающего между двумя заданными температурами. Такой двигатель, работающий по идеальному обратимому циклу (циклу Карно), имеет КПД, который зависит только от абсолютных температур нагревателя ($T_1$) и холодильника ($T_2$), выраженных в Кельвинах:$\eta_{max} = \frac{T_1 - T_2}{T_1} = 1 - \frac{T_2}{T_1}$.</p><p>Эта формула показывает предельное значение КПД, которое не может быть превышено ни одним тепловым двигателем, работающим в том же температурном интервале. КПД любого реального двигателя всегда будет меньше КПД идеального двигателя Карно из-за необратимых процессов, таких как трение, неполное сгорание топлива, теплообмен с окружающей средой и т. д.</p><p>Анализ формулы для максимального КПД показывает пути его повышения:</p><p><strong>1.</strong> <strong>Повышение температуры нагревателя ($T_1$)</strong>. Чем выше температура, при которой рабочее тело получает тепло, тем больше может быть КПД. Это основной путь повышения эффективности современных тепловых двигателей, который ограничен жаропрочностью материалов, из которых изготовлен двигатель.</p><p><strong>2.</strong> <strong>Понижение температуры холодильника ($T_2$)</strong>. Чем ниже температура, при которой отводится тепло, тем выше КПД. Однако на практике температура холодильника обычно близка к температуре окружающей среды (атмосферы, воды в реке), и ее существенное понижение затруднительно и экономически невыгодно.</p><p>Таким образом, КПД является ключевым показателем экономичности и совершенства теплового двигателя, показывающим, какая доля подведенной тепловой энергии превращается в полезную работу.</p><p><strong>Ответ:</strong> Коэффициент полезного действия (КПД) теплового двигателя — это отношение полезной работы, совершенной двигателем за цикл, к количеству теплоты, полученному от нагревателя. Он рассчитывается по формуле $\eta = \frac{A_{полезная}}{Q_1} = 1 - \frac{Q_2}{Q_1}$, где $Q_1$ — теплота от нагревателя, а $Q_2$ — теплота, отданная холодильнику. Согласно второму закону термодинамики, КПД всегда меньше 100%, так как невозможно всю теплоту преобразовать в работу. Максимально возможный КПД для идеального двигателя (двигателя Карно) определяется абсолютными температурами нагревателя ($T_1$) и холодильника ($T_2$): $\eta_{max} = 1 - \frac{T_2}{T_1}$. Повысить КПД можно за счет увеличения температуры нагревателя или уменьшения температуры холодильника.</p>"
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            "text" => "<p><strong>Коэффициент полезного действия (КПД) теплового двигателя</strong> — это физическая величина, характеризующая эффективность преобразования тепловой энергии, полученной от нагревателя, в полезную механическую работу. КПД, обозначаемый греческой буквой $\eta$ (эта), является безразмерной величиной и часто выражается в процентах.</p><p>Любой тепловой двигатель работает циклически и для его работы необходимы:</p><p><strong>1.</strong> <em>Нагреватель</em> — источник тепловой энергии с высокой температурой $T_1$, от которого рабочее тело (например, газ или пар) получает количество теплоты $Q_1$.</p><p><strong>2.</strong> <em>Рабочее тело</em> — вещество, которое совершает механическую работу при расширении.</p><p><strong>3.</strong> <em>Холодильник</em> — объект с низкой температурой $T_2$, которому рабочее тело отдает некоторое количество теплоты $Q_2$, не преобразованное в работу.</p><p>За один цикл работы двигатель совершает полезную работу $A_{полезная}$, которая, согласно закону сохранения энергии (первому началу термодинамики), равна разности между количеством теплоты, полученным от нагревателя, и количеством теплоты, отданным холодильнику:$A_{полезная} = Q_1 - Q_2$.</p><p>По определению, КПД равен отношению полезной работы, совершенной двигателем, к количеству теплоты, полученному от нагревателя:$\eta = \frac{A_{полезная}}{Q_1}$.</p><p>Подставив выражение для работы, получим основную формулу для КПД реального теплового двигателя:$\eta = \frac{Q_1 - Q_2}{Q_1} = 1 - \frac{Q_2}{Q_1}$.</p><p>Из второго закона термодинамики следует, что невозможно создать тепловой двигатель, который бы полностью преобразовывал всю полученную теплоту в работу. Это означает, что всегда есть тепловые потери, и часть энергии ($Q_2$) неизбежно передается холодильнику. Следовательно, $Q_2 &gt; 0$, а значит, КПД любого реального теплового двигателя всегда меньше 1 (или 100%).</p><p>Французский инженер Сади Карно в 1824 году определил максимально возможный КПД для теплового двигателя, работающего между двумя заданными температурами. Такой двигатель, работающий по идеальному обратимому циклу (циклу Карно), имеет КПД, который зависит только от абсолютных температур нагревателя ($T_1$) и холодильника ($T_2$), выраженных в Кельвинах:$\eta_{max} = \frac{T_1 - T_2}{T_1} = 1 - \frac{T_2}{T_1}$.</p><p>Эта формула показывает предельное значение КПД, которое не может быть превышено ни одним тепловым двигателем, работающим в том же температурном интервале. КПД любого реального двигателя всегда будет меньше КПД идеального двигателя Карно из-за необратимых процессов, таких как трение, неполное сгорание топлива, теплообмен с окружающей средой и т. д.</p><p>Анализ формулы для максимального КПД показывает пути его повышения:</p><p><strong>1.</strong> <strong>Повышение температуры нагревателя ($T_1$)</strong>. Чем выше температура, при которой рабочее тело получает тепло, тем больше может быть КПД. Это основной путь повышения эффективности современных тепловых двигателей, который ограничен жаропрочностью материалов, из которых изготовлен двигатель.</p><p><strong>2.</strong> <strong>Понижение температуры холодильника ($T_2$)</strong>. Чем ниже температура, при которой отводится тепло, тем выше КПД. Однако на практике температура холодильника обычно близка к температуре окружающей среды (атмосферы, воды в реке), и ее существенное понижение затруднительно и экономически невыгодно.</p><p>Таким образом, КПД является ключевым показателем экономичности и совершенства теплового двигателя, показывающим, какая доля подведенной тепловой энергии превращается в полезную работу.</p><p><strong>Ответ:</strong> Коэффициент полезного действия (КПД) теплового двигателя — это отношение полезной работы, совершенной двигателем за цикл, к количеству теплоты, полученному от нагревателя. Он рассчитывается по формуле $\eta = \frac{A_{полезная}}{Q_1} = 1 - \frac{Q_2}{Q_1}$, где $Q_1$ — теплота от нагревателя, а $Q_2$ — теплота, отданная холодильнику. Согласно второму закону термодинамики, КПД всегда меньше 100%, так как невозможно всю теплоту преобразовать в работу. Максимально возможный КПД для идеального двигателя (двигателя Карно) определяется абсолютными температурами нагревателя ($T_1$) и холодильника ($T_2$): $\eta_{max} = 1 - \frac{T_2}{T_1}$. Повысить КПД можно за счет увеличения температуры нагревателя или уменьшения температуры холодильника.</p>"
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                }
              ]
              #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" => 5155
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Мнемозина"
                    "field_cases" => null
                    "field_translit" => "mnemozina"
                  ]
                  #original: array:6 [
                    "id" => 5155
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Мнемозина"
                    "field_cases" => null
                    "field_translit" => "mnemozina"
                  ]
                  #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:2 [
                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" => 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 => "*"
                  ]
                }
                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" => 4263
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Дик"
                    "field_bio" => null
                    "field_degree_rp" => null
                    "field_foreign_lang_name" => null
                    "field_foreign_lang_patronymic" => null
                    "field_foreign_lang_surname" => null
                    "field_name" => "Юрий"
                    "field_patronymic" => "Иванович"
                    "field_surname_rp" => null
                  ]
                  #original: array:12 [
                    "id" => 4263
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Дик"
                    "field_bio" => null
                    "field_degree_rp" => null
                    "field_foreign_lang_name" => null
                    "field_foreign_lang_patronymic" => null
                    "field_foreign_lang_surname" => null
                    "field_name" => "Юрий"
                    "field_patronymic" => "Иванович"
                    "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 {#1172
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_book_type" => Illuminate\Database\Eloquent\Collection {#1173
              #items: array:1 [
                0 => App\Models\Term {#1174
                  #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" => 6671
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Учебник"
                    "field_book_type_foreign" => null
                    "field_cases" => array:6 [ …6]
                    "field_plural_form" => null
                    "field_short_name" => null
                    "field_short_name_foreign" => null
                    "field_translit" => "uchebnik"
                  ]
                  #original: array:10 [
                    "id" => 6671
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Учебник"
                    "field_book_type_foreign" => null
                    "field_cases" => array:6 [ …6]
                    "field_plural_form" => null
                    "field_short_name" => null
                    "field_short_name_foreign" => null
                    "field_translit" => "uchebnik"
                  ]
                  #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 {#1175
              #items: array:1 [
                0 => App\Models\Term {#1176
                  #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 [ …6]
                    "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 [ …6]
                    "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 {#1177
              #items: array:1 [
                0 => App\Models\Term {#1178
                  #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 [ …6]
                    "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 [ …6]
                    "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 {#1179
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_umk" => Illuminate\Database\Eloquent\Collection {#1180
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1181
              #items: array:1 [
                0 => App\Models\Term {#1182
                  #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" => 38
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "базовый"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "bazovyy"
                  ]
                  #original: array:6 [
                    "id" => 38
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "базовый"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "bazovyy"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1183
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_publication_number" => "7"
            "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1184
              #items: array:1 [
                0 => App\Models\Term {#1185
                  #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" => 33
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "стереотипное"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "stereotipnoe"
                  ]
                  #original: array:6 [
                    "id" => 33
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "стереотипное"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "stereotipnoe"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1186
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_under_the_edition_degree" => null
            "field_cover_description" => null
            "field_publication_year" => "2009"
            "field_publication_year_until" => null
            "field_part" => "1, 2"
            "field_part_writing" => "Часть"
            "field_second_foreign_language" => null
            "field_for_whom" => "Учебник для общеобразовательных организаций"
            "field_allowed" => null
            "field_reserve_field" => null
            "field_link_to_source" => null
            "field_tasks_count" => "740"
            "field_priority" => null
            "field_default_folder" => "/fizika_10/gendenshtejn-u-09/"
            "field_isbn" => "978-5-346-03674-6"
            "field_cover" => array:1 [
              0 => "/media/fizika_10/gendenshtejn-u-09/covers/cover1.webp?ts=1757890317"
            ]
            "field_cover_alts" => array:1 [
              0 => ""
            ]
            "field_covers" => array:1 [
              0 => array:4 [
                "path" => "/media/fizika_10/gendenshtejn-u-09/covers/cover1.webp?ts=1757890317"
                "alt" => ""
                "width" => "1637"
                "height" => "2568"
              ]
            ]
            "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/gendenshtejn-uchebnik-2009"
            "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1190
              #items: []
              #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" => 1937
            "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 {#1165}
            "field_publisher" => Illuminate\Database\Eloquent\Collection {#1167}
            "field_author" => Illuminate\Database\Eloquent\Collection {#1169}
            "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1172}
            "field_book_type" => Illuminate\Database\Eloquent\Collection {#1173}
            "field_country" => Illuminate\Database\Eloquent\Collection {#1175}
            "field_city" => Illuminate\Database\Eloquent\Collection {#1177}
            "field_series" => Illuminate\Database\Eloquent\Collection {#1179}
            "field_umk" => Illuminate\Database\Eloquent\Collection {#1180}
            "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1181}
            "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1183}
            "field_publication_number" => "7"
            "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1184}
            "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1186}
            "field_under_the_edition_degree" => null
            "field_cover_description" => null
            "field_publication_year" => "2009"
            "field_publication_year_until" => null
            "field_part" => "1, 2"
            "field_part_writing" => "Часть"
            "field_second_foreign_language" => null
            "field_for_whom" => "Учебник для общеобразовательных организаций"
            "field_allowed" => null
            "field_reserve_field" => null
            "field_link_to_source" => null
            "field_tasks_count" => "740"
            "field_priority" => null
            "field_default_folder" => "/fizika_10/gendenshtejn-u-09/"
            "field_isbn" => "978-5-346-03674-6"
            "field_cover" => array:1 [
              0 => "/media/fizika_10/gendenshtejn-u-09/covers/cover1.webp?ts=1757890317"
            ]
            "field_cover_alts" => array:1 [
              0 => ""
            ]
            "field_covers" => array:1 [
              0 => array:4 [
                "path" => "/media/fizika_10/gendenshtejn-u-09/covers/cover1.webp?ts=1757890317"
                "alt" => ""
                "width" => "1637"
                "height" => "2568"
              ]
            ]
            "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/gendenshtejn-uchebnik-2009"
            "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
    }
    "page" => Illuminate\Database\Eloquent\Collection {#1380
      #items: array:1 [
        0 => App\Models\BookPage {#1195
          #connection: "mysql"
          #table: "book_pages"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:21 [
            "id" => 1405581
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_page_start" => "265"
            "field_url" => "/10-klass/fizika/gendenshtejn-uchebnik-2009/page-265"
            "field_display_title" => "265"
            "field_folder" => "1"
            "field_image_name" => "265"
            "field_branch_parent" => Illuminate\Database\Eloquent\Collection {#1198
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_weight" => "0"
            "field_book_parent" => Illuminate\Database\Eloquent\Collection {#1193
              #items: array:1 [
                0 => App\Models\Book {#1199
                  #connection: "mysql"
                  #table: "books"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:50 [
                    "id" => 1937
                    "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 {#1200 …2}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1202 …2}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1204 …2}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1206 …2}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1209 …2}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1210 …2}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1212 …2}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1214 …2}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1216 …2}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1217 …2}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1218 …2}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1220 …2}
                    "field_publication_number" => "7"
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1221 …2}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1223 …2}
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => null
                    "field_publication_year" => "2009"
                    "field_publication_year_until" => null
                    "field_part" => "1, 2"
                    "field_part_writing" => "Часть"
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебник для общеобразовательных организаций"
                    "field_allowed" => null
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№4 (с. 265)
Условие. №4 (с. 265)
скриншот условия
Физика, 10 класс Учебник, авторы: Генденштейн Лев Элевич, Дик Юрий Иванович, издательство Мнемозина, Москва, 2009, страница 265, номер 4, Условие

4. Расскажите о коэффициенте полезного действия теплового двигателя.

Решение. №4 (с. 265)

Коэффициент полезного действия (КПД) теплового двигателя — это физическая величина, характеризующая эффективность преобразования тепловой энергии, полученной от нагревателя, в полезную механическую работу. КПД, обозначаемый греческой буквой $\eta$ (эта), является безразмерной величиной и часто выражается в процентах.

Любой тепловой двигатель работает циклически и для его работы необходимы:

1. Нагреватель — источник тепловой энергии с высокой температурой $T_1$, от которого рабочее тело (например, газ или пар) получает количество теплоты $Q_1$.

2. Рабочее тело — вещество, которое совершает механическую работу при расширении.

3. Холодильник — объект с низкой температурой $T_2$, которому рабочее тело отдает некоторое количество теплоты $Q_2$, не преобразованное в работу.

За один цикл работы двигатель совершает полезную работу $A_{полезная}$, которая, согласно закону сохранения энергии (первому началу термодинамики), равна разности между количеством теплоты, полученным от нагревателя, и количеством теплоты, отданным холодильнику:$A_{полезная} = Q_1 - Q_2$.

По определению, КПД равен отношению полезной работы, совершенной двигателем, к количеству теплоты, полученному от нагревателя:$\eta = \frac{A_{полезная}}{Q_1}$.

Подставив выражение для работы, получим основную формулу для КПД реального теплового двигателя:$\eta = \frac{Q_1 - Q_2}{Q_1} = 1 - \frac{Q_2}{Q_1}$.

Из второго закона термодинамики следует, что невозможно создать тепловой двигатель, который бы полностью преобразовывал всю полученную теплоту в работу. Это означает, что всегда есть тепловые потери, и часть энергии ($Q_2$) неизбежно передается холодильнику. Следовательно, $Q_2 > 0$, а значит, КПД любого реального теплового двигателя всегда меньше 1 (или 100%).

Французский инженер Сади Карно в 1824 году определил максимально возможный КПД для теплового двигателя, работающего между двумя заданными температурами. Такой двигатель, работающий по идеальному обратимому циклу (циклу Карно), имеет КПД, который зависит только от абсолютных температур нагревателя ($T_1$) и холодильника ($T_2$), выраженных в Кельвинах:$\eta_{max} = \frac{T_1 - T_2}{T_1} = 1 - \frac{T_2}{T_1}$.

Эта формула показывает предельное значение КПД, которое не может быть превышено ни одним тепловым двигателем, работающим в том же температурном интервале. КПД любого реального двигателя всегда будет меньше КПД идеального двигателя Карно из-за необратимых процессов, таких как трение, неполное сгорание топлива, теплообмен с окружающей средой и т. д.

Анализ формулы для максимального КПД показывает пути его повышения:

1. Повышение температуры нагревателя ($T_1$). Чем выше температура, при которой рабочее тело получает тепло, тем больше может быть КПД. Это основной путь повышения эффективности современных тепловых двигателей, который ограничен жаропрочностью материалов, из которых изготовлен двигатель.

2. Понижение температуры холодильника ($T_2$). Чем ниже температура, при которой отводится тепло, тем выше КПД. Однако на практике температура холодильника обычно близка к температуре окружающей среды (атмосферы, воды в реке), и ее существенное понижение затруднительно и экономически невыгодно.

Таким образом, КПД является ключевым показателем экономичности и совершенства теплового двигателя, показывающим, какая доля подведенной тепловой энергии превращается в полезную работу.

Ответ: Коэффициент полезного действия (КПД) теплового двигателя — это отношение полезной работы, совершенной двигателем за цикл, к количеству теплоты, полученному от нагревателя. Он рассчитывается по формуле $\eta = \frac{A_{полезная}}{Q_1} = 1 - \frac{Q_2}{Q_1}$, где $Q_1$ — теплота от нагревателя, а $Q_2$ — теплота, отданная холодильнику. Согласно второму закону термодинамики, КПД всегда меньше 100%, так как невозможно всю теплоту преобразовать в работу. Максимально возможный КПД для идеального двигателя (двигателя Карно) определяется абсолютными температурами нагревателя ($T_1$) и холодильника ($T_2$): $\eta_{max} = 1 - \frac{T_2}{T_1}$. Повысить КПД можно за счет увеличения температуры нагревателя или уменьшения температуры холодильника.

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Мы подготовили для вас ответ c подробным объяснением домашего задания по физике за 10 класс, для упражнения номер 4 расположенного на странице 265 к учебнику 2009 года издания для учащихся школ и гимназий.

Теперь на нашем сайте ГДЗ.ТОП вы всегда легко и бесплатно найдёте условие с правильным ответом на вопрос «Как решить ДЗ» и «Как сделать» задание по физике к упражнению №4 (с. 265), авторов: Генденштейн (Лев Элевич), Дик (Юрий Иванович), базовый уровень обучения учебного пособия издательства Мнемозина.