Potential Difference / Voltage (T2)

Question 1

What is potential difference?

Answer 1

The work done when a coulomb of charge passes between two points on an electrical circuit.

A potential difference (AKA voltage) across an electrical component is needed to make a current flow through it.

A measure of potential energy that can be delivered into or out of a circuit by each coulomb of charge that flows around it.

Question 2

How would you measure potential difference in a circuit?

Answer 2

Potential difference is measured using a voltmeter.

This must be connected in parallel with the component.

Question 3

How do you calculate potential difference?

Answer 3

V = W / Q

Or..

V = I x R

V = potential difference in volts
W = energy transferred in joules
Q = charge in coulombs
I = current in amps
R = resistance in Ohms

Question 4

Describe how potential difference works with regards to cells..

Answer 4

A typical cell can deliver around 1.5V.

When two or more cells are connected in series, the total potential difference is the sum of their potential differences.

Eg: If two 1.5V cells are connected in series in the same direction, the total potential difference is 3.0V.

If they are in opposite directions they cancel out at 0.0V.

Question 5

When two or more components are connected in series the potential difference of the supply is…

Answer 5

…shared between them.