Một nguồn điện có điện trở  trong là 1Ω và suất điện động là 6V.Mắc một điện trở 4Ω vào hai cực của nguồn thành một mạch kín. Công suất mạch ngoài khi đó bằng 

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Một số câu hỏi khác có thể bạn quan tâm.

• Choose the best answer for the following sentence:

  Our company is ______________ contract to supply enough materials for them to produce.

   

• Choose the best answer for the following sentence:

  The volunteers are keen __________ coming to that remote area.

   

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

  It was them that killed the bank manager.

• Choose the best answer for the following sentence:

  Most parents have total confidence ___________  the school.

   

• Choose the best answer for the following sentence:

   Friends make us ___________ more comfortable and cheerful in life.

   

• Choose the best answer for the following sentence:

  ''If you are late again, I will sack you,'' the boss ___________ him.

   

• Choose the best answer for the following sentence:

  John said that at 9 o’clock the day before he ____________ the monthly report.

   

• Choose the best answer for the following sentence:

  He offered ______________ these bags.

   

• Choose the best answer for the following sentence:

  John ______________ for London three years ago.

   

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

  She invited us to her birthday party last week.