Every card in Electricity and magnetism, Year 7: more practice
The whole deck, in order — so you can read it through before your child ever sees it.
- Two bar magnets are placed with their north poles facing each other. What do the magnets do?
They repel each other
HintThink about what happens to like poles.
WhyLike poles repel and unlike poles attract. This is why two north poles resist being pushed together, even though they are not touching.
- A bar magnet is cut in half. What do you get?
Two smaller magnets, each with a north and a south pole
HintCan you ever separate one end from the other?
WhyEvery piece of a magnet has both poles, however small the piece. Cutting never separates north from south.
- Around a bar magnet, in which direction do magnetic field lines point outside the magnet?
From the north pole to the south pole
HintLines leave one end and arrive at the other.
WhyThe arrows on field lines show the direction a free north pole would be pushed. Outside the magnet, that is away from north and towards south.
- On a drawing of a magnetic field, where is the field strongest?
Where the field lines are closest together
HintLook at how crowded the drawn arrows are.
WhyField lines bunch up near the poles, where the magnet's push and pull is strongest, and spread out further away.
- The north-seeking end of a compass needle points to the Earth's geographic north. What kind of magnetic pole must lie near there?
A magnetic south pole
HintUnlike poles attract.
WhyThe compass needle's north end is attracted to the Earth's pole near the geographic north, so that pole behaves as a magnetic south pole.
- Why can a compass give a wrong reading if it is held close to a steel toolbox?
The steel affects the compass needle
HintWhat is the pointer sensitive to?
WhyA compass needle is a small magnet. Steel near it becomes magnetised and its field is stronger than the Earth's weak field, so the needle points the wrong way.
- A polythene rod is rubbed with a cloth and gains electrons. Is the rod now positively or negatively charged?
Negatively charged
HintElectrons carry a particular kind of charge.
WhyElectrons are negatively charged. Gaining them leaves the rod with more negative charge than positive, so it is negatively charged.
- When a balloon rubbed on wool sticks to a wall, which kind of particles were moved by the rubbing?
Electrons
HintOnly one kind of charged particle is free to move.
WhyOnly electrons move; the protons stay fixed in the atoms. The material that loses electrons ends up positive and the one that gains them negative.
- A charged rod is repelled by a rod known to be negatively charged. What is the charge on the first rod?
Negative
HintWhich kinds of pair push apart?
WhyOnly like charges repel. Attraction would not prove anything, because a charged rod also attracts an uncharged one, but repulsion does.
- Two balloons hang side by side, one positively and one negatively charged. What do they do?
They move towards each other
HintOpposites do something that like charges do not.
WhyUnlike charges attract. The balloons pull together without touching, so the force is a non-contact force.
1★ KS3-PHYS-ELE-0041
2★ KS3-PHYS-ELE-0042
3★ KS3-PHYS-ELE-0043
4★ KS3-PHYS-ELE-0044
5★ KS3-PHYS-ELE-0045
6★ KS3-PHYS-ELE-0046
7★ KS3-PHYS-ELE-0047
8★ KS3-PHYS-ELE-0048
9★ KS3-PHYS-ELE-0049
10★ KS3-PHYS-ELE-0050
Keep what you learn
Here, nothing is saved. In your child’s own sky every card is scheduled — it comes back just before they’d forget it — and the professor who wrote it is one tap away.