Question

A 12 HP motor has to be operated 8 hours/day. How much will it cost at the rate of 50 paisa/kWh in 10 days

• A. Rs. 350/-
• B. Rs. 358/-
• C. Rs. 375/-
• D. Rs. 397/-

Answer 1

The correct option is B

Rs. 358/-

If a motor of 12 HP works for 10 days at the rate of 8 hr/day then energy

consumption = power $\times$ time

$=12\times 746\frac{J}{sec}\times (10\times 8\times 60\times 60)sec$

$=12\times 746\times 80\times 60\times 60J=2.5\times {10}^{9}J$

Rate of energy = $50\frac{paisa}{kWh}$

$i.e3.6\times {10}^{6}Jenergycost0.5Rs$

So $2.5\times {10}^{9}J$ energy cost = $\frac{2.5\times {10}^9}{2\times 3.6\times {10}^6}$ = 358 Rs