Question

An electric toaster draws 8A current in a 220 V circuit. It is used for 2 hours. What is the cost of operating the toaster if the cost of electrical energy is Rs. 4.5 per kWh?
A. Rs. 9.50
B.Rs. 25.50
C.Rs. 14.84
D.Rs. 15.84

Answer 1

In this question, we have been asked to calculate the cost of energy required to operate the toaster for a given time. Therefore, we need to calculate the energy used by the toaster per second. We know that electrical energy is given as the product of power used and the time, the duration for which the toaster is used. Therefore, we will be calculating the power for a given time.
Formula Used: - $E=P\times t$

Complete step-by-step solution
It is given that an electric toaster draws 8A current in a 220V circuit. We are asked to calculate the cost of operating the toaster.
Therefore, we will calculate the electric energy used by toaster
We know,
$E=P\times t$
We also know that power is given as the product of voltage and current in a circuit
Therefore,
$P=V\times I$
Therefore, from (1) and (2)
We get,
$E=V\times I\times t$
After substituting given values
We get,
$E=220\times 8\times 2$
Therefore,
$E=3520Wh$
It can also be written as,
$E=3.52kWh$
It is given that cost of using electrical energy is 4.5 per kWh. Therefore, the cost of energy for 3.52 kWh can be given by,
$C=3.52\times 4.5$
Therefore,
$C=15.84$
Hence, the cost of operating the toaster at a price of Rs. 4.5 per kWh is Rs. 15.84.
Therefore, the correct answer is option D.

Note: For any element of the circuit, the power is given as the product of the voltage applied across the element and the current flowing through the element. The energy resulting from the flow of electric charge is known as electric energy. Electric energy is given as the product of time for which the electric power is consumed and electric power.