Question

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

• A. 86.4 s
• B. 4.32 s
• C. 43.2 s
• D. 8.64 s

Answer 1

Answer: (C)

$T=2\pi \sqrt{\frac{\ell }{g}}$
$\frac{\Delta T}{T}=\frac{1}{2}\frac{\Delta \ell }{\ell }$
$\Delta T=\frac{1}{2}\times \frac{0.1}{100}\times 24\times 3600$
$\Delta T=43.2$