Question

In the arrangements A and B shown below, pins P and Q stick to an iron loop and an iron rod with the help of wax. In which case are the both pins likely to fall at different times? Explain.

Answer 1

In case B both pins are likely to fall at different times.
In solids, generally, the heat is transferred by the process of conduction. Thus, the predominant mode of heat transfer in the iron rod is conduction.
In case A, heat by the process of conduction reaches both pins simultaneously. Hence, both pins will fall at the same time.
In case B, heat by the process of conduction first reaches to pin P then to pin Q.
Hence, in case B, pin Q will fall after the pin P.