# Current through a circuit with switches

• Physics197
In summary, the current through bulb 1 increases when switch 1 is opened and when both switches 1 and 3 are opened. It stays the same when switch 2 is opened and increases when switch 3 is opened. This is due to the fact that when switch 1 is opened, all of the current flows through bulb 1, and when both switches 1 and 3 are open, all of the current must go through bulb 1 and 5.

## Homework Statement

http://i.imagehost.org/view/0578/bulbsb [Broken]
Consider the current flowing through bulb 1. In each situation, does the current through bulb 1 increase, decrease, or stay the same.

1. All switches are closed, then switch 1 is opened.
2. All switches are closed, then switch 2 is opened.
3. Then switch 1 is also opened.
4. Finally, switch 3 is opened as well.

I = V/R

## The Attempt at a Solution

1. Increase - rather than splitting the current between bulbs 1 and 2/3, all of the current can go through 1.
2. stay the same? - this would only increase bulb 6?
3. Increase - similar to 1
4. increase - all the current must go through bulb 1 and 5 now

Last edited by a moderator:
It seems you exchanged S2 and S3. (or questions 2 and 4). The rest is Ok.

## 1. What is current and how is it measured?

Current is the flow of electric charge through a circuit. It is measured in units of amperes (A).

## 2. Why do circuits need switches?

Circuits need switches to control the flow of current. By opening or closing a circuit, switches can turn devices on or off, or change the direction of current flow.

## 3. How does current change when switches are open or closed?

When a switch is open, current cannot flow through that part of the circuit. When a switch is closed, current can flow through that part of the circuit.

## 4. What is the difference between an open and closed circuit?

An open circuit is incomplete and does not allow current to flow. A closed circuit is complete and allows current to flow.

## 5. How can I calculate the current in a circuit with switches?

To calculate the current in a circuit with switches, you will need to use Ohm's Law, which states that current (I) equals voltage (V) divided by resistance (R). You will also need to take into account the effects of any open or closed switches in the circuit.

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