Question

A 1 k W motor supplies 1200 litre of water pre minute. If demand increases 1800 litre/minute, then what should be the power of new motor used keeping other things in supply system unchanged?

• A. 27/8 Kw
• B. 9/4 Kw
• C. 27/4 kW
• D. 18/4 Kw

Answer 1

Answer: (D)

18/4 Kw

Answer 2

p' = n³p

where n = $\frac{1800}{1200} = \frac{3}{2}$

p' = $\left( \frac{3}{2} \right)^{3}$. 1kW = $\frac{27}{8}$ kW