Всего 3 во тестовой формы, очень надо В каких средах с ростом температуры проводимость увеличивается?
а) в металлах
б) в вакууме
в) в полупроводниках
г) во всех
2. В находится примерно 18*10^23 молекул газа. Определите количество вещества.
а) 0,5 моль
б) 0,5 кмоль
в) 3 моль
г) 3 кмоль
3. С какой по величине силой взаимодействуют заряды 2 Кл и 1Кл, на расстоянии 2 м между их центрами?
а) k
б) 2k
в) k/2
г) 4K
Рубиновый лазер преимущественно работает в импульсном режиме и генерирует излучение на длине волны =0,6943 мкм. Из-за возможностей получения больших импульсных мощностей, а также наличия рубиновых кристаллов высокого оптического качества рубиновый лазер и в настоящее время один из наиболее известных твердотельных лазеров.
Рубин – драгоценный материал, в чистом виде редко встречающийся в природе. Это диамагнитный кристалл окиси алюминия Al2O3 (-корунда) c парамагнитными примесными ионами хрома Cr3+. В зависимости от концентрации хрома кристалл -корунда принимает различные цвета: 0,5% Cr – ярко красная, более 8% Cr- зеленый цвет кристалла.
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