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

• demode
In summary, ten 110-ohm lamps are connected in parallel to a 110-V house line. The combined resistance of the lamps is 11 ohms, the current flowing in the line when all ten lamps are operating is 10 amps, and the power supplied to the circuit by the line is 1100 watts. The conversation also discussed the formula for calculating total resistance for resistors in parallel, as well as using Ohm's law to find current and power in a circuit.
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?

Looks good to me.

~Lyuokdea

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!

## What are resistors in parallel?

Resistors in parallel are a type of electrical circuit in which the resistors are connected side by side, allowing current to flow through multiple paths. This results in a lower total resistance compared to a single resistor.

## How do you calculate the total resistance of resistors in parallel?

The total resistance of resistors in parallel can be calculated using the formula 1/Rt = 1/R1 + 1/R2 + 1/R3 ... where Rt is the total resistance and R1, R2, R3, etc. are the individual resistances.

## What is the effect of adding more resistors in parallel?

Adding more resistors in parallel decreases the total resistance of the circuit. This means that more current can flow through the circuit, increasing the overall power output.

## What happens if one resistor in parallel fails?

If one resistor in parallel fails, the overall resistance of the circuit will decrease, allowing more current to flow. This could potentially lead to overheating and damage to other components in the circuit.

## How does the voltage drop across each resistor in parallel compare?

In a parallel circuit, the voltage drop across each resistor is the same. This is because the voltage is divided evenly among the resistors, with each one receiving the same amount of voltage.

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