Two circular disc `A` and `B` with equal radii are blackened. They are heated to same temperature and are cooled under identical conditions. What inference do your draw from their cooling curves?

Options

A. A and B have same specific heats
B. Specific heat of A is less
C. Specific heat of B is less
D. Nothing can be said

Answer

B

Explanation

Rate of cooling –
`(dQ)/(dt)=-(e A sigma)/(mc)(theta^4 - theta_0^4)`
- ve sign indicate that temperature decreases.
`implies (dQ)/(dt) prop 1/c`
For A, rate of cooling is large, specific heat of A is smaller.