For the following three light bulbs for use in your home, find the current and r
ID: 1429473 • Letter: F
Question
For the following three light bulbs for use in your home, find the current and resistance of each bulb.
a) Calculate the total cost of ownership (TCO) of each bulb assuming that you pay $0.15/kWh. TCO is how much money you spend to buy and use the light bulb for its expected life.
b) Calculate how much money you would spend on lighting your home using the three bulbs. How can you compare these three technologies? What light bulb would you recommend using and why?
Power
Life (hours)
Cost
Incandescent
100W
1500
$0.85
CFL
25W
3500
$1.55
LED
22W
50,000
$11.99
Power
Life (hours)
Cost
Incandescent
100W
1500
$0.85
CFL
25W
3500
$1.55
LED
22W
50,000
$11.99
Explanation / Answer
Given,
P1 = 100 W ; P2 = 25 W and P3 = 22 W
We know standard voltage in USA for dowmstoc use is 120 Volts at 60 Hz.
We know that, P = V I = V2/R
I1 = P1/V = 100/120 = 0.83 A
R1 = V2/P1 = 120 x 120 / 100 = 144 Ohm
I2 = P2/V = 25/120 = 0.21 A
R2 = V2/P2 = 120 x 120 / 25 = 576 Ohm
I3 = P3/V = 22/120 = 0.18 A
R3 = V2/P3 = 120 x 120 / 100 = 654.55 Ohm
P1 = 0.1 kW
for 1500 Hrs, P = 0.1 x 1500 = 150 kWhr
Cost for 150 kWhr = 0.15 x 150 = 22.5 $
P2 = 87.5 kWhr
cost for 87.5 kWhr = 0.15 x 87 = 13.05 $
P3 = 1100 kWhr
cost for 1100 kWhr = 165 $
LED bulbs should be used. Less power consumption. Life is very long. Cost effective.