What is the current in each bulb?

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SUMMARY

In a parallel circuit with two 40-watt bulbs connected to a 120-volt source, the current through each bulb is determined to be 1/3 Amp. The calculation involves using the power formula P = V^2/R to find the equivalent resistance, but it is unnecessary for determining the current in each bulb. The total current for the circuit is 2/3 Amp, which is then divided equally between the two bulbs, resulting in 1/3 Amp per bulb.

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Two 40-watt bulbs are connected in parallel to a 120-volt circuit. What is the current in each bulb?
Choose one answer.
a. 1/4 A
b. 1/3 A
c. 1/2 A
d. 2 A
e. 3 A

I used V = IR and P = V^2/R

My attempt
40 W = 120V^2 / R giving R = 360
1/R + 1/R = 1/Req => 1/360 + 1/360 = 1/Req => Req = 180ohms
V=IR => 120 = 180I => I = 2/3
which is not an answer
 
Last edited:
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You found the total current (correctly), but the question asks for the current through each bulb.
 


You don't need to calculate resistance here, assume the total current is [tex]I[/tex] , then [tex]I= \frac{80w}{120V}=\frac{2}{3} Amp[/tex], the current in each bulb should be [tex]\frac{1}{3} Amp[/tex]
 

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