A barometer made of a very narrow tube is placed at normal temperature and pressure. The coefficient of volume expansion of mercury is `0.00018` per degree centigrade and that of the tube is negligible. The temperature of mercury in the barometer is now raised by `1^@C`, but the temperature of the atmosphere does not change. Then, the mercury height in the tube remains unchanged.

Explanation

`h=(P_(0))/(rhog)`