Practice Questions CBSE - Science Class 10 (2023 Boards)

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Question 37 (a) - Choice 1 [Case Based]

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Question 39 (d) - Choice 2 [Case Based] Important

The frequency of AC in some countries is 60 Hz. What does this mean?

A. The current changes direction 60 times in a second.

B. The current changes direction 120 times in a second.

C. The current changes direction after every 60 seconds.

D. The current changes direction after every 120 seconds

 

Answer. 

  • The frequency of an AC signal is the number of cycles per second in an AC sine wave. Here, there are 60 cycles per second .
  • In each cycle , the current changes direction twice :
    • Positive to negative
    • Negative to positive

 

Therefore, in a signal of frequency 60Hz, the current would change direction 120 times in a second .

The correct answer is B .

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CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo