1 kWh is equal to ________J *
a) 3.6 ×106 J
b) 36 × 106 J
c) 3.6 × 105 J
d) 3600 J
4. A ball of mass m
 

Solution
One kilowatt-hour (1 kWh) is equivalent to a power of 1 kW being used for 1 hour,

 1 k W h = l kilowatt × 1 hour = 1000 watts × 3600 seconds = 3,600,000 watt-seconds or joules  = 3.6 x 10⁶  J