Question

name the physical quantity used to express the amount of water vapour present in air

Answer 1

Your answer is Relative humidity.

Hope this helps you.

Answer 2

The water-vapor substance of the environment changes from place to put and every now and then in light of the fact that the moistness limit of air is controlled by temperature.

At the point when the air is damp, it has a great deal of water vapor in it.

Water as a gas in the air is called water vapor.

At 30 °C (86 °F), for instance, a volume of air can contain up to 4 percent water vapor.

The most extreme measure of water vapor that can be noticeable all around relies upon the air temperature.