Question

Mention the commercial unit of energy. Express it in terms of joules. Calculate the energy in joule consumed by a device of 60 W in 1 hour.

Answer 1

Commercial unit of Energy is Kilo Watt per hour denoted by kWh. 

1kWh = 3600000 Joules 

Energy Consumed in 1 hour 

60 W = 60 j/s 

1 hour = 60×60 seconds 

⇒ Energy consumed in 1 hour = 60 × 60 × 60 = 216000 j 

216000 Joules of energy is consumed in 1 hour.