Đặt vào hai đầu biến trở R một nguồn điện không đổi ξ₁, r₁. Thay đổi giá trị R thì thấy công suất tiêu thụ trên mạch ngoài theo biến trở được biểu diễn như hình vẽ (đường nét liền). Thay nguồn điện trên bằng nguồn điện ξ₂, r₂ và tiếp tục thay đổi biến trở thì thấy công suất tiêu thụ trên mạch ngoài có đồ thị như đường nét đứt. Tỉ số  gần nhất giá trị nào sau đây? 

Chia sẻ

Một số câu hỏi khác có thể bạn quan tâm.

• Choose the best answer for the following sentence:

  __________ playing professional basketball, she also enjoys tennis.
   

• Choose one sentence that has the same meaning as the root one:

  "I saw her in the park two hours ago," said he.
   

• Choose one sentence that has the same meaning as the root one:

  "Joe has a lot on his mind, " Mrs Baker said.
  
  

• Choose one sentence that has the same meaning as the root one:

  I'll break a promise if I tell you her name.
  
  

• Choose one sentence that has the same meaning as the root one:

  "I'm leaving here for Da Lat next week," said Mrs Lan.
  
  

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

  Though her difficult living condition, Marie worked extremely hard to earn a degree.

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

  A United Nations tried to solve some global environmental problems.

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

  I really think that apologizing is a little you can do now.

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

  seafood                   release                    threaten                 beneath  

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

  however                   know                      follow                    show