Question

When we pay for electricity bill, we are paying for the:
A. Charge used
B .Current used
C. Power used
D. Energy used

Answer 1

Hint: We use electricity to use machines like fans, grinder and washing machine. All of them use electricity to do work. When we pay electricity bills, the quantity is measured in kilowatt-hour$(kWh)$,meaning 1000 joules/sec for 1 hour. Electric usage is given in units of kilowatt-hour per month$1(kWh)=3.6\times {{10}^{6}}J$

Formula used: $Electrical\; energy= power\times time$.

Complete solution Step-by-Step:
We must have observed that a person from the electricity board visits our house on a monthly basis to take the readings of the electricity consumed by us. The more the load, more the electrical energy consumed. Similarly, lesser the load, lesser the electrical energy consumed.
When we pay for electricity bills, we are paying for the electrical energy consumed. We as a domestic users pay for energy= \[\dfrac{rms\text{ }Voltage\times rms\text{ }current\times \text{ }power\text{ }factor\times Hours}{1000}\] which is called kilowatt-hour$(kWh)$ or units on a monthly basis A unit of electricity is defined in terms of $(kWh)$, means 1000 joules/sec for 1 hour.

Where, $Electrical\; energy= power\times time$.
It is often measured in kilowatt-hour$(kWh)$.

Whereas, Charges flow in our household circuit and go back to the source. So, we do not hold any charge with us. Also current is flow of charges and varies from time to time. In order to measure time, we must always keep reading, which is not the case we observe. Again, power is defined as the rate of doing work, and hence doesn’t account for the time period during which work is done.
Rather, energy is a term which sums up charge, current and power over a period of time.

Hence, D. When we pay for electricity bill, we are paying for the energy used, is the answer

Note:
1.Be careful with the units and powers. $Electrical\; energy= power\times time$., for energy= \[\dfrac{rms\text{ }Voltage\times rms\text{ }current\times \text{ }power\text{ }factor\times Hours}{1000}\] .It is often measured in kilowatt-hour$(kWh)$.$1(kWh)=3.6\times {{10}^{6}}J$.
2. A unit of electricity is defined in terms of $(kWh)$, meaning 1000 joules/sec for 1 hour. Electric usage is given in units of kilowatt-hour per month$1(kWh)=3.6\times {{10}^{6}}J$.