A person decides to use his bath tub water to generate electric power to run a 40 W bulb. The bath tub is located at a height of h m from ground an it holds V liters of water. He installs a water driven wheel generator on ground. The rate at which water should drain from bath tub to light the bulb if efficiency of machine be 90% is
A
B
44.44 ρ ρ gh
C
D
Text Solution
Verified by ExpertsThe correct answer is:
C
Power = P= 
(mgh) = 
or P = 
= 
Since η η = 
∴ ∴ P output = η η P input = η η ρ ρ gh 
or 
= 
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