Physics electristy

What is current?

The flow of electric charge.

What is the unit of current?

Amps (A)

What is potential difference (voltage)?

The energy transferred per unit charge.

What is the unit of potential difference?

Volts (V)

What is resistance?

How much a component opposes current.

Formula linking charge, current, and time?

Q=It

Formula linking potential difference, current, and resistance?

V=IR

What does a power supply do?

Provides potential difference to push charge around a circuit.

What happens to current in a series circuit?

It is the same everywhere.

What happens to potential difference in a series circuit?

It is shared between components.

What happens to current in a parallel circuit?

It splits between branches.

What happens to voltage in a parallel circuit?

It is the same across each branch.

What is electrical power?

The rate of energy transfer in a circuit.

Power formula (using V and I)?

P=VI

Alternative power formula?

P=I2R

What happens when resistance increases?

Current decreases (if voltage stays constant).

What is an ohmic conductor?

A component where current is directly proportional to voltage.

What causes resistance in a wire?

Collisions between electrons and ions.

A current of 2A flows for 5 seconds. Calculate charge.

Q = 2 × 5 = 10 C

A device has resistance 4Ω and current 3A. Find voltage

V = 3 × 4 = 12 V

Explain why current is the same in a series circuit.

• There is only one path

• Charge cannot split

• Same number of electrons pass each point

• So current is equal throughout

Explain how increasing resistance affects current.

• Resistance opposes current

• More collisions in the wire

• Makes it harder for charge to flow

• So current decreases