Potential Difference and Electromotive Force

Question 1

Electromotive Force

Answer 1

The energy converted into electrical energy when 1C of charge passes through it.

Question 2

Battery

Answer 2

• Pump that moves electrons
• Does work, so energy is changed within it
• Produces an EMF

Question 3

Potential Difference

Answer 3

P.D between two points is the energy generated for 1C passing between them.

1 volt = 1 joule per coulomb

Question 4

EMF vs PD

Answer 4

EMF - a source providing electrical energy

PD - device converting electrical energy to other forms

EMF can be thought of as terminal PD when no current is being drawn from the source.

Question 5

What does a voltmeter measure?

Answer 5

Potential difference

Question 6

Terminal PD

Answer 6

Reading on a voltmeter across battery terminals

Question 7

Internal resistance

Answer 7

Possessed by all sources.

E = V + v

V is voltage across an external load resistor

v is the voltage lost to internal resistance

Question 8

Electrical Power

Answer 8

The rate at which electrical energy is converted to other forms of energy by a circuit or a component, such as a resistor, in a circuit.

P = IV