## What is the equivalent resistance between terminals B and A?

The resistance between terminals A and C is therefore 5 ohms.

**What is the equivalent resistance between points A and B in Figure? **

The equivalent resistance between A-B is RAB=R1+R2=r+r=2r, since R1 and R2 exist in series.

### What is the equivalent resistance between the points A and D?

Now all resistance between points A and D becomes in series. We can therefore add all of them together to get the equivalent resistance. Hence, we can conclude that option (C) R=30O is the correct answer.

**How do you find the equivalent resistance between two points? **

The two resistances R1 and R2 of 4 ohms are in series therefore their equivalent resistance,

- R’=4 O + 4 O=8 O
- Now the resistances R’ and R3 are in parallel, so the equivalent resistance for the circuit would be.
- Therefore the equivalent resistance between the two points A and B in the given circuit is 1. 85 O.

## How do you find the current through a resistor in parallel and series?

The current through the circuit is the same for each resistor in a series circuit and is equal to the applied voltage divided by the equivalent resistance: I=VRS=9V90O=0.1A. The sum of all potential drops across each resistor equals the voltage supplied to it by the battery.

**How do you find the voltage after a resistor? **

Voltage Drop: Series Circuit

- Calculate the total resistance by adding the individual R values.
- Calculate the current in the circuit, which is the same across each resistor since there is only one wire in the circuit.
- Calculate the voltage drop across each resistor using Ohm’s law.

### Does the voltage stay the same in a series circuit?

Each part of a series circuit is subject to the same current. The sum of all resistances in a series circuit equals the total resistance. The voltage applied to a series circuit equals the sum of individual voltage drops.

**What remains the same in a series circuit? **

The current in a series circuit will be the same at every resistor in the circuit. Each light bulb will have the same resistance (“identical lights”) and the same current. They will therefore have the same power output (P=I2R, as explained in the previous Lesson).