Physics · Current Electricity | MDCAT MCQ

Question

An electric iron is 20V & 500W . The unit consumed by it (in kJ) in using it for 24 hours will be:

Options

A
12 units
B
24 units
C
5 units
D
1100 units

Explanation

Power = energy/time

500 = E/24

E = 500 x 24

= 12,000 J

Here, the power of the electric iron is given as 500 watts (or 0.5 kilowatts) and the time is 24 hours. So, the energy consumed would be: 0.5 kW x 24 hours = 12 kWh (kilowatt-hours). In terms of units, 1 kWh is equal to 1 unit. Thus, the iron would use 12 units of electricity in 24 hours.

Incorrect as per formula