The rain water from a roof 22m by 20m drains into a conical vessel having the diameter of base as 2m and height 3.5m. If the vessel is just full, find the rainfall in mm.
Total rain fall = Volume of vessel =13×π×(22)2×3.5
=3.5π3m3
= Area of roof × height of rainfall
⇒3.5π3=22×20×h
⇒R=3.5π3×22×20m=3.5π×10003×22×20mm
=7×22×10007×6×22×20=506mm=8.33mm