Question

4. The total time taken by a seconds pendulum
to complete 20 oscillations is
(a) 20 s
(b) 38 s
(c) 40 s
(d) 42 s

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Answer 1

Answer:

c) 40 s

A pendulum takes 2 seconds for the completion of 1 oscillation, 1 forth and 1 to come back.

Time taken = oscillation×2

= 20 × 2

=40