Q34 of 146 Page 163

A certain household consumes 650 units of electricity in a month. How much is this electricity in joules?

Energy equal to one kwh is termed as one unit.

So 650 units equal to 650 kwh.

Now 1 kwh = 3.6 × 10⁶

So,

650kwh = 650 × 3.6 × 10⁶

= 2340 × 10⁶

How much electric energy in kWh is consumed by an electrical appliance of 1000 watts when it is switched on for 60 minutes?

Derive the relation between commercial unit of energy (kWh) and SI unit of energy (joule).

Define power. Give the SI unit of power.

A boy weighing 40 kg carriers a box weighing 20 kg to the top of a building 15 m high in 25 seconds. Calculate the power. (g = 10 m/s²)