Question

Same material is used to make a sphere, a cube and a thin circular plate and having the same mass. They are initially heated to a temperature of 3000°C. Which of these will cool fast?

(a) Sphere

(b) Cube

(c) Plate

(d) All thee will cool at the same rate

The question was posed to me in semester exam.

I'm obligated to ask this question of Latent Heat in section Kinetic Theory of Gases of Engineering Physics I

Answer 1

Correct answer is (c) Plate

To elaborate: All three have the same mass and hence the same volume. Therefore the plate has a maximum surface area. So, the plate will cool fastest.