Answer:
(a) = $34.123
(b) = $8.532
(c) Additional cost of fluorescent bulb is justified
Explanation:
Cost of electricity = $0.17 per kW·h
(a) For a 100 watt bulb which is the same as 100/1000 or 0.1 kW, the cost per hour =
0.1 × 0.17 = $0.017/h
and for 5.5 hours = 0.017×5.5 = $0.0935
The annual cost, which is 365 days, we have
Annual cost = $0.0935 × 365 = $34.123
(b) For the energy efficient 25-watt bulb, we have
25/1000 = 0.025kW
Power cost per annum =
0.025kW×$0.17 per kW·h×5.5×365 = $8.532
(c) Total cost of incandescent bulb = $0.89 total cost of using the incandescent bulb is $34.123 + $0.89 = $35.02
Total cost of using the energy efficient fluorescent bulb is about $3.49
Total cost of using the energy efficient bulb = $8.532 + $3.49 = $12.02
Total cost of incandescent bulb = $35.02 while total cost of energy efficient bulb is = $12.02
$12.02 <$35.02
Additional cost of fluorescent bulb is justified
