Question

An electric kettle is rated 2.5 kW- 250 V. Find the cost of running the kettle for two hours at 60 paisa per unit.

Answer 1

Step 1- Given data

Time, $t=2hours$

The power rating of the bulb, $P=2.50kW$

Cost per unit, $r=₹0.6perunit$

Potential difference, $V=250V.$

Step 2- To calculate the energy consumed in kWh-

The formula for Energy consumed is, $E=P\times t$

$$\begin{gathered} E=2.50\times \left(2\right) \\ \Rightarrow E=5kW-h \\ \Rightarrow E=5units. \end{gathered}$$

Step 3- To calculate the running cost -

$$\begin{gathered} Running\cos t=r\times E \\ \Rightarrow Running\cos t=\left(₹0.6\right)\times \left(5units\right) \\ \Rightarrow Running\cos t=₹3 \end{gathered}$$

Thus, the running cost of the lamp for two hours a day is$₹3.$