Three 45.0-W, 100-V lightbulbs are connected across a ? V = 100-V power source,
ID: 1309002 • Letter: T
Question
Three 45.0-W, 100-V lightbulbs are connected across a ?V = 100-V power source, as shown in the figure below. Find the total power delivered to the three bulbs and the potential difference across each. Assume the resistance of each bulb is constant (even though, in reality, the resistance increases markedly with current).
(a) Find the total power delivered to the three bulbs.
The answer to this part is 30.03 W.
(b) Find the potential difference across each bulb.
V
Please and Thank you!
?VR1 = V ?VR2 = V ?VR3 =V
Please and Thank you!
Explanation / Answer
Req = R + R/2 = 3R/2 =1.5R
45 = (100)^2/R
R=222.22ohm
Req=333.33 ohm
a) P = V^2/REq = (100)^2/(333.33) =30 W
b) Vr1 = 200/3 = 66.67V
Vr2 = Vr3 = 100/3 = 33.33V