Question

The air in a room has 15 gm of water vapour per cubic meter of its volume. However the saturation of one cubic meter of volume requires 20gm of water vapour then relative humidity is :

• A. $50$%
• B. $75$%
• C. $20$%
• D. $25$%

Answer 1

The correct option is B $75$%

Relative humidity = $\frac{m}{M}\times$100%
Where m is the mass of vapour actually present in certain volume of air & M is the mass required to saturate the air fully of that volume.
So, R.H = $\frac{15}{20}\times 100$ = 75%