How Do You Calculate Resistance, Current, and Power in Parallel Circuits?

[demode]

1. Ten 110-ohm lamps are connected in parallel to a 110-V house line. A) What is the combined resistance of the ten lamps? B) What current flows in the line when all ten lamps are operating? C) What power is then being supplied to the circuit by the line?

I just wanted to have someone check my work and see if I attacked this problem the right way.



2. 1 / Rt = 1 / r1 + 1 / r2... (total resistance for resistors in parallel)
V = IR
P = VI




3. A) This is simple: add (1/110) ten times, giving (1/11).. Then cross multiplication can be used to find that Total resistance is equal to 11 ohms

B) To find the current that flows in the line, we can use ohms law and substitute 110 volts = 11 ohms * I, and I will evaluate to 10 amps

C) P = (110 volts)(10 amps) = 1100 right?

 

[Lyuokdea]

Looks good to me.

~Lyuokdea

 

[m2003]

Your approach to solving this problem is correct. In parallel circuits, the total resistance is calculated by taking the reciprocal of each individual resistance and adding them together. In this case, since all resistances are the same (110 ohms), the total resistance will be 1/110 + 1/110 + ... + 1/110 = 1/11 ohms.

To find the current, you can use Ohm's law (V = IR). The voltage is given as 110 volts and the total resistance is 1/11 ohms, so the current will be 110 volts / (1/11 ohms) = 10 amps.

Finally, to find the power being supplied by the line, you can use the equation P = VI. Substituting the values from the previous calculations, we get P = (110 volts)(10 amps) = 1100 watts. This is the total power being supplied to the circuit by the line.

Overall, your approach and calculations are correct. Good job!