Question

A tube light of 40 W runs at 220 V. What is the current in the tube light and how much energy in kWh it will consume in 10 hours?

Answer 1

Step 1: Given data:

$$\begin{gathered} Power=40W \\ Voltage=220V \\ Time=10hours \end{gathered}$$

Step 2: Find the current of the tube light:

$$\begin{gathered} \because Power\left(P\right)=Voltage\left(V\right)xCurrent\left(I\right) \\ \therefore Current,I=\frac{P}{V} \\ I=\frac{40}{220} \\ =0.18A \end{gathered}$$

Step 3: Find the energy consumed by the tubelight:

$$\begin{gathered} Eneryconsumed\left(kWh\right)=Power\left(kW\right)xRunningtime\left(hr\right) \\ =40x10 \\ =400kWh. \end{gathered}$$

Hence, the tube light of $40W$ running at $220V$ will consume $400kWh$ energy, whereas $0.18A$ current is passing from the same tube light.