Question

How is thermal expansion is applied in detecting temperature by mercury thermometer?

Answer 1

Answer:

1. These liquid thermometers are based on the principal of thermal expansion. 
2. As the temperature of the liquid in a thermometer increases, its volume increases.
3. To read a mercury thermometer, hold it between your finger and thumb and turn it until you can see the point on the scale
4. The basic principle of thermometry is that when the two bodies in contact and in thermal equilibrium will have the same temperature.

Answer 2

Answer:

Mercury has uniform thermal expansion. Thus when temperature raised by 1 unit , it expand its volume by x unit. If Temperature is increased by 2 units , it would increase its volume by 2x unit. Thus based on this they calibrate the thermometer and we can use it to find temperature.