Assertion (A): A 1000 W bulb when used for 1 hour consumes the same number of electrical units as that of 100 W bulb that is used for 10 hours.
Reason (R ) : On electrical unit is charged when one kilowatt hour electrical energy is consumed.

Options

A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true, but R is not the correct explanation of A.
C. A is true but R is false.
D. Both A and R are false.

Answer

A

Explanation

We know, 1 unit = 1 kWh = 1000 W h = 1000 W`xx` 1 h = 100 W x 10 h So, 100 W bulb used for 10 h and 1000 W bulb used for 1 h consumes same amount of electrical energy, i.e., 1 kWh or one electrical unit.