- #1
kamhogo
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Homework Statement
A 60 W lightbulb and a 100 W lightbulb are placed one after another ( in series, the 60 W battery closer to the positive terminal of the battery) in a circuit. The battery's emf is large enough that both bulbs are glowing. Which is the true statement?
A. The 60 W bulb is brighter
B. Both bulbs are equally bright
C. The 100 W bulb is brighter.
D. There's not enough information to tell which is brighter.
Homework Equations
Pr = Pbat = I*Epsilon
I = Pr/ delta Vr
Pr= I * delta Vr = (I^2)*R = ( ( delta Vr)^2)/R
The Attempt at a Solution
I know the answer is A because the book says so, I just don't understand why. I would have gone with D.
The current is the same in both bulbs ( conservation of current). And R = Pr/(I^2). So the 60 W bulb should have a smaller resistance than the 100 W ( the internet says otherwise ). Stuck. Please help.