A gravity settling chamber of height ' $H$ ' and length ' $L$ ' is designed to control particulate air pollution. In the chamber, the horizontal velocity of air flow is ' $V_{h}$ ' and terminal settling velocity of the target particle is ' $V_{t}$ '.
Which one of the following expressions is the correct concept used to calculate the minimum size of the target particle that will be removed with $100 \%$ efficiency?
- $\frac{V_{t}}{L}=\frac{V_{h}}{H}$
- $V_{h} \times V_{t}=L \times H$
- $V_{h}=V_{t} \times L \times H$
- $\frac{V_{t}}{H}=\frac{V_{h}}{L}$
