Question

What is the unit of coefficient of area expansion?

(a) per °C

(b) °C

(c) per (°C)^2

(d) (°C)^2

The question was posed to me during an interview for a job.

Question is taken from Thermal Expansion topic in chapter Thermal Properties of Matter of Physics – Class 11

Answer 1

The correct answer is (a) per °C

Explanation: The coefficient of area expansion is defined as (ΔA/A)/ΔT. So we see that its unit is per °C. Note that all the coefficients of thermal expansion, namely linear, area & volume have the same unit.