Question

How much energy is consumed by

(a) a $1.2$kW hair dryer used for $10$min and

(b) a $10$ W night light left on for $24$ h?

Short answer

a). Energy consumed by hairdryer $7.2\times {10}^5$J

b). Energy consumed by night light$8.64\times {10}^5$J

Step-by-step solution

Step 1. Given Information

For hair dryer

Power $P=1.2kW=1200W$

Duration $t=10min=600s$

For night light

Power$P=10W$

Duration$t=86400s$

Step 2. a). Energy consumed by hairdryer

We need to determine the energy consumed by hairdryer for above mentioned situation

$$\begin{gathered} W=Pdt \\ W=1200\times 600 \\ W=720000 \\ W=7.2\times {10}^{5}J \end{gathered}$$

Step 3. Part b). Energy consumed by night light

$$\begin{gathered} W=Pdt \\ W=10\times 86400 \\ W=8.64\times {10}^{5}J \end{gathered}$$