How to culculate rms current using Watts in a Household Curcuit

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Homework Help Overview

The discussion revolves around calculating the RMS current in a household circuit with three lamps of varying wattages. The original poster presents a scenario involving two 150W bulbs and one 100W bulb, seeking to determine the current and resistance for each lamp using provided equations.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants explore the necessity of knowing the voltage to calculate current and resistance. The original poster questions how to apply Ohm's law without specific voltage or time variables.

Discussion Status

Some participants suggest assuming standard household voltages, with one confirming the use of 120V for US circuits. There is recognition that voltage is essential for the calculations, but no consensus on the method has been reached.

Contextual Notes

The original poster notes a lack of information regarding voltage and time, which complicates their ability to apply the equations effectively. The discussion highlights the importance of these variables in solving the problem.

jmmckiss
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Homework Statement



Three lamps are connected in a household curcuit. Lamps 1 and 2 have 150W bulbs and lamp 3 has a 100W bulb. What is the Current (I) and Resistance (R) of each bulb?

Homework Equations



V=IR P = W/t = (V*q)t = V*I

I= q/t V= W/q

The Attempt at a Solution



Lamp 1
V=150W*1.6*10^-19 C?

i'm not sure how to do this exactly. my teacher didn't explain very thoroughly. No time variable is given, no voltage, or current. I don't know how I can use Ohm's law.
 
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Can you assume standard household voltage ( like in India it is 220V rms)?
 
YEp!

I can assume a voltage, for the US household curcuot it's 120 V, and I can plug that into the P=VI to get my answer.Thanks!
 
Just for info - It can't be done any other way. You have to know the voltage.
 

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