Year 7: Electricity - Voltage, Current & Resistance

Key word definition

electron A negative particle in the atom

Proton A positive particle in the atom

Neutron A neutral particle in the atom

Circuit symbol

A symbol to represent an electrical device

Ammeter A device for measuring Current

Voltmeter A device for measuring potential difference

Volts Unit for potential difference (V)

Amps Unit for current (A)

ohms Unit for resistance (W)

There are two types of charge.Positive (Proton) & Negative (Electron)Like charges repelUnlike charges attract.

Question: A bulb has a current of 4A and a potential difference of 6V, what is resistance?

An Insulator can be charged by rubbing (Friction)

The flow of charge is called electric current. It can be measured using an Ammeter. It is always in series.

A cell or battery can push chargesalong, we call this push potential difference. It can be measured using a Voltmeter. It is always in parallel.

𝑅𝑒𝑠𝑖𝑎𝑡𝑛𝑐𝑒 (Ω)=𝑃𝑜𝑡𝑒𝑛𝑖𝑎𝑙 𝑑𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑉

𝐶𝑢𝑟𝑟𝑒𝑛𝑡 𝐴

The resistance of a piece of material can be changed by:• Changing its length• Changing its thickness• Changing the material

The resistance of the material increases linearly with length.