2.3 Units And Measurements

Question 1

What is current?

Answer 1

Current is the flow of electrons (negatively charged particles) around a circuit. Current flowing around a circuit can be compared to water flowing round a pipe.

Current (I) is measured in Amperes (A).

Question 2

What is voltage?

Answer 2

The force used to ‘push’ the electrons round the circuit. Also known as the electromotive force. Can be viewed as the ‘pump’ which pushes the water round the pipes.

Voltage (V) is measured in Volts (V).

Question 3

What is resistance?

Answer 3

Resistance is a measure of how good a material is at conducting electricity.

Resistance is measured in Ohms (Ω).

Question 4

What is the calculation for voltage?

Answer 4

V= I x R

Voltage (V)= Current (I) x resistance (R)

Question 5

What is ohms law?

Answer 5

Ohm’s law states that the current through a conductor between two points is directly proportional to the voltage across the two points.

I= V/R
Current (I) = Voltage (V) / Resistance (R)