posted by Alemu on .
A string of 8 christmas tree lights connected in series to a 120v source draws a current of 0.75A.can any one show me how to find the resistance of each lights and potential differnces.
Since the lights are in series, the potential drop at each light is equal, and can be calculated by 120V/8=15V.
The current, I=0.75 is identical for all the christmas lights connected in series.
Applying V=IR for each light, we get
Use Ohm’s Law
If you read the lesson, you should know the equation for this:
R = V/A
where R is resistance, V is voltage, and A is amperes, so:
R = 120/0.75 = 160.
Since it is a series circuit, each of the bulbs should experience an equal amount of voltage and current. Thus, the same amount of resistance. Divide 160 by 8:
160/8 = 20
So 20 units of Omega