Question

Humidity is measured by __________.
A.Thermometer
B.Hygrometer
C.Barometer
D.Hydrometer

Answer 1

Hint: Humidity is the presence of water vapour in the air which is measured by an instrument to determine the amount of moisture present in the air. There are three different types of humidity - Absolute humidity, specific humidity and relative humidity.

Complete answer: When water evaporates from land and different water bodies, it becomes water vapour. So, the presence of moisture in the air at any time is known as humidity. In simple terms, the capacity to hold the water vapour increases as the air gets warmer and so it becomes more and more humid.
Types of humidity –
1. Absolute humidity is the weight of the actual amount of water present in a unit volume of air, expressed as grams per cubic metre of air.
2. The weight of water vapour per unit weight of air, expressed as grams per kilogram of air is Specific humidity.
3. Relative humidity is the ratio of the air’s actual water vapour content to its water vapour capacity at a given temperature, expressed as a percentage.
A hygrometer is an instrument that is used in meteorological science to measure the amount of water vapour in the air, in confined spaces or in soil. Water vapour present in air varies from zero to four per cent by volume of the atmosphere.
Now let us examine the options
Option A – Thermometer is a device which is used for measuring the temperature of the liquid, gaseous or of any solid matter such as food or of a chemical reaction like fire.
Option B – Hygrometer is used to measure the amount of water vapour in the air, in confined spaces or in soil.
Option C – Barometer is a weather instrument used to measure the atmospheric pressure, that is, the layers of air wrapped around the Earth.
Option D – Hydrometer operates on the principles of Archimedes and is used to determine the specific gravity of a liquid which is the ratio of the water density to the ratio of the density of the liquid.
Thus, the correct answer is option (B).

Note: Do not confuse yourself with the term psychrometer. A psychrometer is a type of hygrometer which is also used to measure humidity. The other types of hygrometer are hair hygrometer and electronic hygrometer.