How to culculate rms current using Watts in a Household Curcuit

AI Thread Summary
To calculate the RMS current in a household circuit with three lamps (two 150W and one 100W), the standard household voltage must be assumed, typically 120V in the US or 220V in India. Using the formula P = VI, the current (I) for each bulb can be calculated by rearranging it to I = P/V. The resistance (R) can then be determined using Ohm's law, R = V/I. Without a specified voltage, the calculation cannot proceed, highlighting the necessity of knowing the voltage for accurate results. Understanding these principles is essential for solving similar electrical problems.
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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