Question

The cost of operating an electric motor for $10$ hour which takes $10amp$ at $110V$ is. (The rate is $2Rs/kWh$ .)

• A. $79200Rs$
• B. $2200$
• C. $220Rs$
• D. $22Rs$

Answer 1

The correct option is D $22Rs$

$V$=$110V$ $I$=$10A$ $t=10hrs$ $Cost=2Rs/kWh$

Electrical power consumption is given by $P=VI$

$P=110\times 10$=$1100Joules/s$

$1$ watt $=1J/sec$ ;

So $P$=$1100Watts$=$\frac{1100}{1000}kW$=$1.1kW$

Total energy consumption in $kWh$ is given by $E=P\times t\left(inhr\right)$

$E=1.1\times 10$=$11kWh$

Total cost $=11\times 2\Rightarrow 22$ Rs. {Option D}