Question

A 100-watt electric bulb is operated for 10 hours. How many units of electrical energy have been consumed?

Answer 1

Step 1: Given

The power (P) of bulb= 100 watt
Time for which bulb is on (t)= 10 hours
let x kWh is the energy consumed by the bulb in 10 hours.

Step 2: Using the formula

$Energy\left(E\right)=power\left(P\right)\times time\left(t\right)$

Substituting the value of P and t we get-

$$\begin{gathered} E=100watt\times 10hours \\ E=1000watt-hours \\ E=1kWh \end{gathered}$$
Hence total unit consumed by the bulb is = 1 kWh= 1 unit.