Question

Let $P_s$ and $P$ be the saturated partial pressure and partial pressure of water respectively, then the relative humidity is given by:

• A. $\frac{P_s+P}{P_s}\times 100$
• B. $\frac{P}{P_s}\times 100$
• C. $\frac{P_s}{P}\times 100$
• D. $(P+P_s)\times 100$

Answer 1

Answer: (B)

$\frac{P}{P_s}\times 100$

Relative humidity

$\varphi =\frac{\text{partial pressure of water vapour}}{\text{(Saturated pressure of pure water vapour at same temperature)}}\times 100$

$\Rightarrow \varphi =\frac{P}{P_s}\times 100$