Question

What is the power of a pump which takes 10 seconds to lift 100 kg of water to a water tank situated at a height of 20 m? Take $g=10m{s}^{-2}$

• A. $5KW$
• B. $4KW$
• C. $3KW$
• D. $2KW$

Answer 1

The correct option is D

$2KW$

Given, the mass of water m = 100 kg, height h = 20 m, the acceleration due to gravity $g=10m{s}^{-2}$ and time taken t = 10 s.

Now, work done against gravity $W=mgh=100\times 20\times 10=20000J$

We know power $P=\frac{W}{t}=\frac{20000}{10}=2000W=2KW$