In the arrangements A and B shown in the figure below, pins P and Q are fixed to a metal loop and an iron rod with the help of wax. In which case are both the pins likely to fall at different times? Explain.
In case ‘B’, the pin P will fall before the pin Q because the heat will reach pin P first. In case ‘A’, the heat travels in both the directions, therefore, pins P and Q will fall simultaneously.