Physics

Question 1

Positive and negative - attracting and repelling

Answer 1

Positive repels positive
Negative repels negative
Positive attracts negative
Negative attracts positive

Question 2

Which charges do protons, electrons and neutrons have?

Answer 2

Protons have a positive charge
Electrons have a negative charge
Neutrons have no charge

Question 3

What is an electrical field?

Answer 3

An electric field is around a charge, like a gravitational field around a mass. If you put a charged object in an electric field, a force will act on it.

Question 4

What is current?

Answer 4

The amount of charge flowing per second. You can measure the current using an ammeter. Current is measured in amps. You can work out the current by potential difference divided by the resistance.

Question 5

Batteries and cells

Answer 5

Pushes the charge around the circuit. In the wires there are electrons, and when you connect the battery the electrons move. In a torch there a 2 cells; cells used together are called a battery.

Question 6

What is potential difference?

Answer 6

The cell or battery provides the push to make the charge move, this is the potential difference. The potential difference tells you the size of the force on the charges. You measure it using a voltmeter and it is measured in volts. You do this by connecting a voltmeter across it. This is called the rating. You measure potential difference by current x resistance.

Question 7

What is a parallel circuit?

Answer 7

In a parallel circuit there is more than 1 loop. The potential difference across each component is the same as the potential difference across the battery.

Question 8

What is a series circuit?

Answer 8

In a series circuit there is only 1 loop. The potential difference across each component adds up to the potential difference across the battery.

Question 9

What is resistance

Answer 9

Each component has a different resistance. This tells how easy it is for the charges to pass through the component. It is measured in ohms. The current depends on the resistance of the component and the push of the battery. You can work out the resistance by:
Potential difference divided by the current.

Question 10

What are conductors.

Answer 10

Metals are good conductors. They have very low resistance because they have lots of electrons that move.

Question 11

Insulator

Answer 11

Other materials such as plastics do not have many electrons that are free to move, therefore they are not very good conductors.

Question 12

Attracting and repelling poles

Answer 12

North poles repel north poles
South poles repel south poles
North poles attract south poles

Question 13

Magnetic fields

Answer 13

You can find out the shape of a magnetic field by using plotting compasses or using iron fillings. If the magnetic field lines are closer together this show the fields are stronger.

Question 14

Electromagnets

Answer 14

Electromagnets usually have a magnetic materials in the centre of the coil, called a core. If you remove steel from a magnet it stays the same.

Question 15

Making electromagnets stronger

Answer 15

The number of turns, or loops on the coil.
Increase the amount of current in the wire
Change the type of core to a more magnetic material.

Question 16

Energy

Answer 16

Different foods are stores of different amounts of energy. Energy is measured in joules.

Question 17

Conservation of energy

Answer 17

Energy can not be created or destroyed, only transferred. This is called the law of conservation of energy.

Question 18

Energy store

Answer 18

There is energy associated with food and fuels. This type of energy is known as a chemical store. Energy if transferred from the store when you burn the fuel.

Question 19

Transferring energy

Answer 19

Electric current, light and sound are ways of transferring energy between stores.

Question 20

Wasting energy and saving energy

Answer 20

In many situations energy it transferred to the thermal store of the surroundings. This means the energy is dissipated.