Question

A metallic bar of coefficient of linear expansion ${10}^{-5}{K}^{-1}$ is heated from $0^{\circ }C$ to ${100}^{\circ }C$. The percentage increase in its length is

• A. $0.1$%
• B. $1$%
• C. $10$%
• D. $0.01$%
• E. $0,001$%

Answer 1

The correct option is A $0.1$%

Given, $\alpha ={10}^{-5}{K}^{-1}$
and $△T={100}^{-\circ }-0^{\circ }={100}^{\circ }C$
We know that, percentage increase in its length,
$\frac{△l}{l}\times 100=\alpha △T\times 100$
$\frac{△l}{l}={10}^{-5}\times 100={10}^{-3}$
$\therefore \frac{△l}{l}\times 100=0.1$%.