Figures ($A$, $B$ and $C$) show a student reading a doctor’s thermometer. Which of the figure indicates the correct method of reading temperature?

Which of the thermometers, $A$ or $B$, will show a greater rise in temperature? Give a reason for your answer.

A circular metal loop is heated at point $O$ as shown in the figure.

In which direction would heat flow in the loop?

In which order the pins at points $P, Q$ and $R$ fixed with the help of wax fall if points $O, P, Q$ and $R$ are equidistant from each other?

In the arrangements, $A$ and $B$ shown in the figure, 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.