Question

Length of a rod increases 0.2% on increasing the temperature by 100°C. The value of coefficient of linear expansion of material of rod is

• A. \(2 \times 10^{-5}\) per °C
• B. None
• C. \(2 \times 10^{-4}\) per °C
• D. \(3 \times 10^{-5}\) per °C

Hint:

The coefficient of linear expansion is given by \(\alpha = \frac{\Delta L}{L \Delta T}\).

Answer 1

The Correct Option is A

The change in length is: \[\n\Delta L = \alpha L \Delta T\n\] Given \(\Delta L / L = 0.2%\) and \(\Delta T = 100^\circ C\), we solve for \(\alpha\): \[\n\alpha = \frac{0.2%}{100} = 2 \times 10^{-5} \, \text{per}^\circ C\n\] Therefore, the correct answer is \(2 \times 10^{-5}\) per °C.