Question

Bulb of mercury thermometer is dipped in petrol,when it is taken out what happen to the level of mercury in it ?

Answer 1

We know that petrol have low boiling point.
As the bulb of mercury is taken out of petrol, the petrol which is on the surface of bulb evaporates by the heat of surrounding and the thermometer and makes the surface of bulb, cool.
So, the level of mercury will start failing or decreasing.

Answer 2

We know that petrol have low boiling point.

As the bulb of mercury is taken out of petrol, the petrol which is on the surface of bulb evaporates by the heat of surrounding and the thermometer and makes the surface of bulb, cool.

So, the level of mercury will start failing or decreasing.