Question

A circular disc of copper has a symmetrical hole at its centre. The disc is uniformly heated. The diameter of the hole will

• A. increase
• B. decrease
• C. remain the same
• D. become indeterminate

Answer 1

The correct option is A increase

Due to its coefficient of volume expansion,

$\gamma =\frac{1}{V}\frac{dV}{dT}$

the surface area will expand as the temperature is increased, so the diameter of the hole at its centre will also increase.