Question

If the length of a cylinder on heating increases by 2%, the area of its base will increase by

• A. 0.5%
• B. 2%
• C. 1%
• D. 4%

Answer 1

Answer: (D)

4%

Answer 2

$A \propto L^{2}$ ⇒ $\frac{\Delta A}{A} = 2 \cdot \frac{\Delta L}{L}$ ⇒ $\frac{\Delta A}{A} = 2 \times 2 = 4\%$.