Question

A uniform metal rod is used as a bar pendulum. If the room temperature rises by ${10}^{\circ }C$, and the coefficient of linear expansion of the metal of the rod is 2 ´ ${10}^{-6}pe{r}^{\circ }C$ , the period of the pendulum will have percentage increase of

• A. - 2 ´ 10^-3
• B. - 1 ´ 10^-3
• C. 2 ´ 10^-3
• D. 1 ´ 10^-3

Answer 1

The correct option is D

1 ´ 10^-3

Fractional change in period

$\frac{△T}{T}=\frac{1}{2}\alpha △\theta =\frac{1}{2}\times {10}^{-6}\times 10={10}^{-5}$

% change = $\frac{△T}{T}\times 100={10}^{-5}\times 100={10}^{-3}$ %