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JEE Main 2021 (26 Aug, Shift 2) · Errors in Measurement

Errors in Measurement question from JEE Main 2021 (26 Aug, Shift 2)

Q79JEE Main 2021 · 26 AUG · SHIFT 2Easy

Errors in Measurement

If the length of the pendulum in pendulum clock increases by 0.1%, then the error in time per day is:

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Answer: (c)

  1. T=2πl/gT = 2\pi\sqrt{l/g}, so ΔTT=12Δll=12(0.1%)=0.05%\frac{\Delta T}{T} = \frac{1}{2}\frac{\Delta l}{l} = \frac{1}{2}(0.1\%) = 0.05\%
  2. Error in a day =0.0005×86400 s= 0.0005 \times 86400\text{ s}
  3. =43.2 s= 43.2\text{ s}
  4. So the answer is (c) 43.2 s.
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