Question

Find the cost of operating an electric toaster for $2$ hours, if it draws a current of $8A$ on a $110V$ circuit. The cost of electric energy is Rs. $2.50$ per kWh.

• A. $Rs.4.40$
• B. $Rs.6$
• C. $Rs.8.20$
• D. $Rs.2.20$

Answer 1

The correct option is A $Rs.4.40$

Given:

Current $I=8A$

Voltage $V=110Volt$

We know that,

Power $P=V\times I=110\times 8=880W$

The electric toaster consumes $880J$ in one second.

So, the energy consumed in 2 hours is $E=880\times 2\times 3600J$

Total unit consumed in 2 hours $=\frac{880\times 2\times 3600}{3.6\times {10}^6}=1.76kWh$ ($\because 1kWh=3.6\times {10}^{6}J$)

So, the cost of $1.76kWh$ is $c=1.76\times 2.5=Rs.4.40$