Resistance of Light Bulbs in Parallel

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Homework Help Overview

The discussion revolves around the resistance of light bulbs connected in parallel to a 110-V source, with a focus on calculating the resistance of each bulb and determining the power wasted in the leads with a total resistance of 1.6 Ω.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore different methods to calculate the resistance of each bulb, including using the formula Rbulb=V/I and considering the total current and power in the circuit. Questions arise regarding the voltage drop across each bulb and the interpretation of total resistance.

Discussion Status

Some participants have provided guidance on the calculations, confirming that the voltage drop for each bulb is indeed 110V due to the parallel configuration. There is an ongoing exploration of the original poster's confusion regarding their calculations and the resistance values.

Contextual Notes

Participants are discussing the implications of the total resistance of the leads and how it affects the overall calculations. There is a noted uncertainty about the correct application of formulas and the interpretation of results.

Angie K.
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Homework Statement


Eight lights are connected in parallel to a 110-V source by two long leads of total resistance 1.6 Ω.

a. If 302 mA flows through each bulb, what is the resistance of each?

b. What percent of the total power is wasted in the leads?

Homework Equations


V=I
P=V^2/R

R. The attempt at a solution

I found the total resistance to be 45.5298 V but when plugging that into find the resistance of each bulb, I can't seem to get to the right answer. What am I missing here?
 
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Angie K. said:

Homework Statement


Eight lights are connected in parallel to a 110-V source by two long leads of total resistance 1.6 Ω.

a. If 302 mA flows through each bulb, what is the resistance of each?

b. What percent of the total power is wasted in the leads?

Homework Equations


V=I
P=V^2/R

R. The attempt at a solution

I found the total resistance to be 45.5298 V but when plugging that into find the resistance of each bulb, I can't seem to get to the right answer. What am I missing here?

It can be calculated in many ways (how did you do it?).

1) You can find the resistance in one bulb, (Rbulb=V/Ibulb), after that finding Rtotal in 8 bulbs in parallel.
2) You can find the total power, after that using Ptotal=V2/Rtotal
3) You can find the total current, after that using Rtotal=V/Itotal
 
Last edited:
Hesch said:
It can be calculated in many ways (how did you do it?).

1) You can find the resistance in one bulb, (Rbulb=V/Ibulb), after that finding Rtotal in 8 bulbs in parallel.

That is what I used
Rbulb=V/Ibulb
=110V/.302
=364.238 shouldn't that be the resistance of each bulb? Or do I have to find the voltage drop for eacg lightbulb?and divide it by the total current (wouldn't that just give me the resistance for all the bulbs?)
 
The voltage drop for each bulb is 110V (bulbs are in parallel). Your Rbulb is correct, and so is your Rtotal in #1.

But then I cannot understand this in #1:

Angie K. said:
but when plugging that into find the resistance of each bulb, I can't seem to get to the right answer. What am I missing here?

What's your problem here?
 
Last edited:

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