Question

If an electric iron of $1200\mathrm{W}$ is used for $30$ minutes everyday, find electric energy consumed in the month of April.

Answer 1

Step 1: Given

Power of electric iron, $P=1200\mathrm{W}$

Time iron is used for every day is $30\text{min}=\frac{30}{60}\mathrm{hr}=0.5\mathrm{hr}$

Step 2: Formulas used

We know that power, $P=\frac{W}{t}$ where $W$ is the work done or energy consumed

Step 3: Calculate the total time the iron is used

We know that there are $30$ days in the month of April.
So, if the iron is used for $0.5\mathrm{hr}$ every day for $30$ days, the total amount of time it is used is,
$t=0.5\times 30=15\mathrm{hr}$

Step 4: Calculate the energy used

From the formula for power, we get,

$\begin{array}{cc}& P=\frac{W}{t}\\ \Rightarrow & 1200=\frac{W}{15}\\ \therefore & W=18000\mathrm{WH}\\ \therefore & W=18\text{units}\left[1\text{unit}=1000\mathrm{WH}\right]\end{array}$

Therefore, the total amount of energy consumed in the month of April is $18\text{units}$.