Question

Class X Sciences
[papers from previous years]

Calculate the electric energy consumed by a 1200 W toaster in
20 minutes.

Answer 1

As power is given by=electric energy  /time
time-20min=20×60=1200 sec
electric energy=[power × time]
1200×1200=1440000 J=1440kJ

Answer 2

Energy consumed = Power of the gadget/equipment  * time duration used
                         = 1200 W * 20 * 60 sec 
                          = 1440000 Joules
                          = 1, 440 kJ
                         = 1, 440 / 3600  kW-h
                         = 0.40 kWh or units