In a 10 m side square shaped sedimentation tank, the flow rate is 100cum/h, and if the depth of water is 2 m , the detention time (h) is:

Correct option is C

​$$\text{Detention time} = \frac{\text{Volume of tank}}{\text{Flow rate}}$$
$$\text{Plan area of tank} = 10 \times 10 = 100 \ \text{m}^2$$
​​​$$\text{Depth of water} = 2 \ \text{m}$$
$$\text{Volume of tank} = 100 \times 2 = 200 \ \text{m}^3$$
$$\text{Flow rate} = 100 \ \text{m}^3/\text{h}$$
$$\text{Detention time} = \frac{200}{100} = 2 \ \text{h}$$​​​​​