Question

An electric heater is rated 1500W. How much unit of energy does it use in 15 hours?

Answer 1

We know,

Power =$\frac{energy}{time}$

1500 =$\frac{energy}{15\times 60\times 60}$

Energy = 81 * 10⁶ Joule;

Unit of energy =$\frac{81\ast {10}^{6}Joule}{3.6\ast {10}^6}$

= 22.5 units of energy is used.