Đoạn mạch RLC nối tiếp được mắc vào hai cực của một máy phát điện xoay chiều một pha có rôto là nam châm điện một cặp cực. Thay đổi tốc độ quay của rôto. Khi rôto quay với tốc độ 30 vòng/s thì dung kháng của tụ điện bằng R, khi quay với tốc độ 40 vòng/s thì điện áp hiệu dụng hai đầu tụ điện đạt cực đại và khi quay với tốc độ n vòng/s thì cường độ dòng điện hiệu dụng trong mạch đạt giá trị cực đại. Giá trị n là:  

Chia sẻ

Một số câu hỏi khác có thể bạn quan tâm.

• Find a mistake in the four underlined parts of the sentence and correct it:

  The list of the Seven Wonders of the Ancient World is originally compiled around the second century BC.

• Find a mistake in the four underlined parts of the sentence and correct it:

  Today, archaeological evidence reveals some of the mysteries that surrounded the history

  of the Wonders in centuries.

• Find a mistake in the four underlined parts of the sentence and correct it:

  The Statue of Zeus at Olympia was one of the Seven Wonder of the Ancient World.

• Find a mistake in the four underlined parts of the sentence and correct it:

  The circumstances of its eventual destructive are a source of debate that whether it was

  destroyed in a great fire in 475 or not.

• Find a mistake in the four underlined parts of the sentence and correct it:

  More than 80% of home pages in the Web are in English, while the next greatest, German,

  has only 4.5% and Japanese 3.1%.

• Find a mistake in the four underlined parts of the sentence and correct it:

  The number of people with English as a second language are overtaking the number of

  people for whom the language is their mother tongue.
  
  

• Find a mistake in the four underlined parts of the sentence and correct it:

  The most distinguishing differences between American English and British English is in

  pronunciation and vocabulary.

• Find a mistake in the four underlined parts of the sentence and correct it:

  There are wide varieties of American dialects, some of that appear to be diverging markedly from others.

• Find a mistake in the four underlined parts of the sentence and correct it:

  The use of English ethnic dialects vary from region to region and social group to social group.

• Choose the word that has the underlined part pronounced differently from the rest:

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