P5 - Electricity and magnetism

Question 1

What is the law of magnetic poles? [2]

Answer 1

Like poles repel, unlike poles attract

Question 2

What happens to a piece of unmagnetised magnetic material when it touches or is bought near to the pole of a permanent magnet? [2]

Answer 2

It becomes an induced magnet and will be attracted to the magnet

Question 3

Describe temporary magnets [2]

Answer 3

These are made of soft iron and lost their magnetism easily

Question 4

Describe permanent magnets [2]

Answer 4

These are made of steel and retain their magnetism

Question 5

Name the three elements that are magnetic [3]

Answer 5

Iron, cobalt and nickel

Question 6

Why is steel magnetic? [1]

Answer 6

Because it contains iron

Question 7

What is a magnetic field? [1]

Answer 7

The space around a magnet where it produces a magnetic force

Question 8

What is the direction of magnetic field lines?

Answer 8

From North to South

Question 9

Where on a bar magnet is the magnetic field strongest? [2]

Answer 9

Near the poles (the magnetic field lines are closer)

Question 10

Describe how to plot the magnetic field pattern of a bar magnet [3]

Answer 10

1. Place a plotting compass near the pole of a magnet and mark the direction the compass points. 2. Move the compass around the bar magnet marking where the compass points. 3. Join the points up and add an arrow pointing from the north pole to the south pole.

Question 11

Like charges… [1]

Answer 11

repel

Question 12

Unlike charges… [1]

Answer 12

attract

Question 13

How can an object be charged? [2]

Answer 13

Removal or addition of electrons

Question 14

What is an electric field? [1]

Answer 14

A region in which an electric charge experiences a force

Question 15

Describe a conductor and give an example [2]

Answer 15

Something that lets electrons pass through e.g. metals / graphite

Question 16

Describe why an insulator does not allow electrons to pass through easily and give an example [2]

Answer 16

Electrons are tightly held to atoms are are not free to move but can be transferred by rubbing e.g. plastics / glass

Question 17

Describe a semi conductor and give an example

Answer 17

Poor conductors when cold but better when warm e.g. Silicon / Germanium

Question 18

What is the unit of charge? [1]

Answer 18

Coulomb

Question 19

Define current [1]

Answer 19

The flow of charge past a point per unit time

Question 20

What is the equation that relates current (I), charge (Q) and time(t)? [1]

Answer 20

I = Q/t

Question 21

What direction is conventional current? [1]

Answer 21

Positive to negative

Question 22

What direction is the flow of free electrons? [1]

Answer 22

Negative to positive

Question 23

What is used to measure current and how is this connected in a circuit? [2]

Answer 23

An ammeter connected in series

Question 24

Define electromotive force (e.m.f) [1]

Answer 24

The electrical work done by a source in moving unit charge around a complete circuit

Question 25

Define potential difference (p.d) [1]

Answer 25

The work done by a unit charge passing through a component

Question 26

What other word is used for potential difference? [1]

Answer 26

Voltage

Question 27

What are the units of electromotive force and potential difference? [1]

Answer 27

Volts

Question 28

What is use to measure potential difference and how is this connected in a circuit? [2]

Answer 28

Voltmeter connected in parallel