Current, Resistance & Potential Difference

What is potential difference (voltage)?

Work done per unit charge; energy transferred between two points in a circuit.

Unit and symbol for potential difference?

Volts (V)

What is electric current?

Flow of electrical charge.

Unit and symbol for current?

Amperes (A), symbol I

What does the size of the current show?

The rate of flow of charge – how many electrons pass a point each second.

What is resistance?

Opposition to current caused by vibrating atoms slowing electrons.

How does resistance affect current?

Higher resistance → lower current. Lower resistance → higher current.

Conductors vs insulators in terms of resistance?

Good conductors = low resistance. Insulators = high resistance.

Symbol and unit of resistance?

Symbol R, unit Ohms (Ω).

1 Ohm is defined as…

1 volt per ampere (1 V / A).

How can resistance in a circuit be increased?

By adding more resistors or variable resistors.

Current, voltage, resistance equation?

V = I * R

Relationship between resistance and current for a given voltage?

Greater resistance → smaller current. Smaller resistance → larger current.