Which of the following runoff formula is correct w.r.t. Kuitchling formula?

Rain water from roofs can be allowed to flow through the house sewers.

The mixing time of concrete prior to placement should not exceed 20 minutes.

H2S gas is denser than air.

Stream erosion can be caused by excess __

What is the quantity of powder required in 1000 litres of water for sterilization?

What is the power of diminishment of van der Waals force with respect to distance?

Storm water is a major cause of urban flooding.