Electricity and Magnetism

What is an atom and what are its sub-atomic particles?

Basic building block in all matter of the universe

Sub-atomic particles:

• Protones +

• Neutrons which are neutural

• Electrons -

• The overall charge of an atom is 0 as there are the same amount of protons and electrons

What happens when charges interact?

Opposite charges attract and like charges repel

Explain Static Charge

When two insulating are rubbed together there is a build up of static charge, the electrons transfer from one object to another due to friction. This causes the object which gained electons to become negatively charged and the ones loosing electrons positively charged

How does a vandegraph work?

1. When you touch the vandegraph the electrons transfer from the person to the vanndegraph

2. This leaves the person positively

3. This means that every single strand of hair is positively charged

4. Like charges repel causing the hair to stand up and repel

Why do charge objects attract neutral object?

1. When the charged object reaches the neutural object the negative charges in the neutral object back away because like charges repel

2. This leaves the layer closest to the charged object is positive

3. This causes the two objects to stick together as opposite charges attract

4. This is called charging though induction

What is an electric force field?

The area over which a charged objects exerts a force it goes from negative to positive

How does static charged cause lightning?

1. Air particles collide against each other in the cloud this causes a transfer of electrons due to friction.

2. This may cause the bottom of the cloud to become negatively charged and the top positively charged

3. In the neutral earth the negative charges back away as like charges repel

4. This leaves the top layer of the earth positively charged

5. This causes lighting because opposite charges attract and when the force of attraction is strong enough electrons travel though the sky

What is current?

The amount of charge that flows pass a point per second

How does the rope hand model represent current?

1. Rope=electrons in the circuit

2. The amount of rope moving pass a point per second=current

What is the potential difference?

The amount of push or pull the power supply gives for the electrons to move around the circuit.

How can the rope hand model be used to represent Potential Difference?

• The hands pushing represents the power supply

• Pushing it harder represents a higher PD