Question

A circular hole of 15 cm diameter is cut on a copper plate at a temperature of 30 celsius . Find the area of hole at 150 degree celsius.

Answer 1

$$A'=A(1+\alpha(T_2-T_1))=0.25\pi d^2(1+\alpha(T_2-T_1))$$

$$A'=0.25\pi (15)^2(1+1.7\cdot10^{-5}(150-30))=177.075\ cm^2$$