Question

A hole in a brass plate has a diameter of 20mm through what temperature rise must the plate be heated for the diameter to become 20.09mm

Answer 1

$$d'=d(1+\alpha \Delta T)$$

$$\Delta T=\frac{(\frac{d'}{d}-1)}{\alpha}$$

$$\Delta T=\frac{(\frac{20.09}{20}-1)}{19\cdot 10^{-6}}=240\ K$$