Electricity and Magnetism

Question 1

1. What is current?
2. What piece of equipment is used to measure it?
3. What is the unit?
4. What happens to it in:
   a) a series circuit
   b) a parallel circuit?

Answer 1

1. Current is the flow of electrical charge.
2. An Ammeter measures current.
3. Current is measured in amps.

4 a) In a series circuit the current is the same.

b) In a parallel circuit the current is shared.

Question 2

What is resistance and what is the unit?

Answer 2

Resistance describes how hard it is to make a current flow through it.

It is measured in Ohm

Question 3

1. What is voltage?
2. What piece of equipment is used to measure it?
3. What is the unit?
4. What happens to it in:
   a) a series circuit
   b) a parallel circuit?

Answer 3

1. Voltage describes the push of electric charge around a circuit.
2. It is measured with a voltmeter.
3. It is measured in volts.
4. a) In a parallel circuit the voltage stays the same.
   b) In a series circuit the voltage is shared.

Question 4

If a lamp breaks in a parallel circuit what happens to the whole circuit?

Answer 4

The first bulb still lights up as there is still a

circuit.

Question 5

How can you make a lamp brighter in a circuit?

Answer 5

1. Increase the voltage.
2. Put it in a parallel circuit.
3. Increase the resistance of the bulb.

Question 6

What is electricity?

Answer 6

The flow of moving electrons. Atoms are made up of protons, neutrons and electrons. The electrons are free to move and can therefore pass on energy to a neighbouring electron. Metals have free electrons which can move so are good conductors.

Question 7

If a lamp breaks in a series circuit what happens to the whole circuit?

Answer 7

Nothing in the circuit will work as the

Circuit is broken

Question 8

If a lamp breaks in a series circuit what happens to the whole circuit?

Answer 8

Nothing in the circuit will work as the Circuit is broken

Question 9

Describe how you can find the magnetic fields of a bar magnet.

Answer 9

1. Put the bar magnet under a piece of paper.
2. Sprinkle iron filings on top of the paper.
3. The magnetic field should show up on the paper.

Question 10

Use this triangle to work out the following problems:

I = current

V= voltage

R= resistance

a) 6V, 5A
b) 6V, 12 Ohms
c) 15 Ohms, 0.5 A

Answer 10

a) 1.2 ohms
b) 0.5 A
c) 7.5 V

Question 11

Describe static electricity and how it can be transferred.

Answer 11

Static electricity is caused when 2 different materials are rubbed together. Electrons are transferred from one material to the other. Insulators typically pass on electrons which ‘stick’ to the other materials. These electrons do not move so it is ‘static’.

Question 12

How can you make an electromagnet stronger?

Answer 12

1. Add more coils.
2. Increase the voltage/current.
3. Use an iron core.

Question 13

What makes a motor different to an electromagnet?

Answer 13

An electric motor has electricity running through a coil where it will alternate as it passes through two magnets either side.

An electromagnet has a coil around a core which becomes magnetic.

Question 14

Name some magnetic materials:

Answer 14

1. Iron
2. Nickel
3. cobalt
4. steel

Question 15

Draw a diagram and describe how an electric bell works:

Answer 15

When the switch is on it completes the circuit and the electromagnet turns on.

This attracts the arm which hits the bell. The bell arm then breaks the circuit and moves away from the bell.

It then goes back to its original place and the process is repeated until the switch turns off.