Question

For homologous model of a pump built to a scale ratio of 1 : 2, fluid and speed being the same in model and prototype, the ratio of model power to prototype power is

• A. 1/2.82
• B. 1/4
• C. 1/8
• D. 1/32

Answer 1

The correct option is D 1/32

$Power,P\alpha L_r^5{N}_s^3(N_s{)}_m=(N_s{)}_p\frac{P_m}{P_p}={\left(\frac{L_m}{L_p}\right)}^5\times 1={\left(\frac{1}{2}\right)}^5=\frac{1}{32}$