Percentage Change in Volume of a Cube – Rankers Physics

Thermal Expansion: Practice Problem & Solution

Thin copper wire of length \( L \) increases in length by 2% when heated from \( T_1 \) to \( T_2 \). If a copper cube having side \( 10L \) is heated from \( T_1 \) to \( T_2 \) then the percentage change in volume of the cube is
2%
3%
6%
8%

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Thermal Expansion. Understanding the underlying formula is key to arriving at the correct answer below:

The percentage change in length is \( \frac{\Delta L}{L} \times 100 = 2% \). Since volume expansion coefficient is three times the linear expansion coefficient (\( \gamma = 3\alpha \)), the percentage change in volume is \( 3 \times 2% = 6% \).

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