The pressure at the bottom of a water tank is 6P, where P is the atmospheric pressure. If water is drawn out till the level decreases by 25th, then the pressure at the bottom of the tank is
The correct option is C4P Let the height of the water in the tank is h. Difference in pressure, 6P−P=ρwgh Where, ρw is density of water 5P=ρwgh...(1) ∵25th of water taken out from the tank. So, 35th of water is left to exert the pressure. Let P′ be the pressure exerted by the 35th of water at the bottom of a water tank. So, P′=P+35ρwgh P′=P+35×5P [from equation (1)] ⇒P′=4P ∴ Pressure at the bottom of the tank is 4P.