Given,
Number of CFL N= 10
power of each P = 20W
time t = 6 hrs
Now electricity consumed in a day E = PNt
= 20 * 10* 6
= 1200 Wh
= 1200 / 1000 Kwh
= 1.2 Kwh = 1.2 unit
In a month electricity consumed is
= 1.2 * 30
= 36 units
Hence, 36 units is consumed in a month.
Thus energy = 36 *36 * 105 J
= 1.29 * 10 8 J