Question

An electric heater is used for 120 minutes. The electricity bill for 30 days is 60 units. Calculate the power of the electric heater.

Answer 1

In this question we have been asked to calculate the power of an electric heater if it is used for 2 hours daily for a period of 30 days. It is given that for 30 days the electricity bill was 60 units. Now, we know that 1 unit means 1 kWh. Therefore, the energy or work done is given as 60 kWh. Therefore, we shall use the formula for electrical energy to calculate our answer as it deals with power and time.

Formula Used:
$E=P\times t$
E is the energy in kWh
P is the power in kW
t is the total time in hours.

Complete step by step answer:
It is given that the electric heater is used for 120 minutes daily i.e. 2 hours. Therefore, in a month the electric heater was used for a total time of 60 hours. The electrical energy is given as 60 kWh. Therefore, the power can be given by formula,
$E=P\times t$
Solving for power,
$P=\dfrac{E}{t}$
After substituting the values
We get,
$\Rightarrow P=\dfrac{60kWh}{60h}$
Therefore,
$\Rightarrow P=1kW$
Therefore, the power of a given electric heater is 1 kilowatts.

Note:
Kilowatt-hour is the commonly used as a billing unit for electrical energy used by the consumers. Electric power can be defined as the rate at which electric energy is transferred per unit time. We know that energy is the ability to do work or move the object. In case of electric energy, the attraction or repulsion force does the work. Electric energy is generated as a result of flow of charge. Therefore, electric energy is a kinetic energy.