Answer:
45360 kJ
Explanation:
We can calculate energy by multiplying the power by time:
E = P * t
Each bulb has a power rating of 75W.
In 6 hours (3600 seconds) of each day, the energy exerted by each bulb will be:
E = 75 * 6 * 3600 = 1620000J
10 bulbs will therefore exert:
10 * 1620000 J = 16200 kJ
In a week, the energy exerted will be:
16200000 * 7 = 113400 kJ
Since 40% of this energy is wasted as heat, therefore, the amount of energy wasted as heat is:
40/100 * 113400000 = 45360000 = 45360 kJ
