Question

The least count of a stop watch is 1/5 second. The time of 20 oscillations of a pendulum is measured to be 25 seconds. The maximum percentage error
in the measurement of time will be
(1) 0.1%
(3) 1.8%
(2) 0.8%
(4) 8%​

Answer 1

Answer:

Number of oscillation =20

Total time taken for 20 oscillation =25 sec

Time period =25/20=1.25 sec

Least count of watch =0.2 sec

The measurement of time period 1.25 the measuring watch can measure upto 0.2 s thus the watch can measure 1.2 s but the uncertainity remains in the 0.05 s.

1.25 s=1.2+0.05

Thus, error =0.05 sec

Percentage error =(0.05/1.25)×100=4%

Explanation:

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