WorksheetsIGCSE Electromagnetism Quiz
Total questions: 23
Worksheet time: 12mins
A strong electromagnet is used to attract pins.
What happens when the current in the coil is halved?
No pins are attracted.
Some pins are attracted, but not as many.
The same number of pins is attracted.
More pins are attracted.
The diagram shows a transformer.
The input voltage is 240 V.
What is the output voltage?
6 V
12 V
20 V
40 V
A coil carries a current in a magnetic field. The coil experiences a turning effect.
Which device uses this effect?
a d.c. motor
an electromagnet
a relay
a transformer
A magnet is suspended from a spring so that it can move freely inside a stationary coil. The coil is connected to a sensitive centre-zero galvanometer.
The magnet repeatedly moves slowly up and down.
What does the galvanometer show?
a constantly changing reading
a steady reading to the left
a steady reading to the right
a steady reading of zero
A transformer has 50 turns on its primary coil and 100 turns on its secondary coil. An alternating voltage of 25.0 V is connected across the primary coil.
What is the voltage across the secondary coil?
12.5 V
50.0 V
100 V
200 V
A wire is placed between the poles of a horseshoe magnet. There is a current in the wire in the direction shown, and this causes a force to act on the wire.
Three other arrangements, P, Q and R, of the wire and magnet are set up as shown.
Which arrangement or arrangements will cause a force in the same direction as the original arrangement?
P, Q and R
P and Q only
P only
R only
What is an advantage of transmitting electricity at a high voltage?
It is faster.
It is safer.
Less energy is wasted.
Less equipment is needed.
An e.m.f. is induced across a wire when it moves through the magnetic field between the poles of a magnet.
Which electrical device operates because of this effect?
a battery
a cathode-ray tube
a generator
a motor
The diagram shows a flat, rectangular coil placed between the poles of a magnet.
There is a current in the coil that makes it turn in the direction shown in the diagram.
Which change would make the coil turn in the opposite direction?
decreasing the current in the coil
increasing the number of turns on the coil
reversing both the direction of the current in the coil and the poles of the magnet
reversing only the direction of the current in the coil
A transformer has 1000 turns on its primary coil. An input voltage of 12 V is applied to the primary coil, and an output voltage of 120 V is induced across the secondary coil.
How many turns are on the secondary coil of the transformer?
100
120
1000
10 000
Which diagram represents the voltage output of a simple a.c. generator?
A
B
C
D
A step-up transformer is used before electricity is transmitted by overhead cables.
Which statement explains why the step-up transformer is used?
It increases the current to increase the speed at which the electricity travels.
It increases the current to reduce energy loss in the cables.
It increases the voltage to increase the speed at which the electricity travels.
It increases the voltage to reduce energy loss in the cables.
A current-carrying wire XY lies in the magnetic field between the two poles of a U-shaped electromagnet.
A force acts on the wire XY because of the magnetic field.
Each of the following actions is carried out separately.
● The current in the wire XY is reversed.
● The magnetic field is reversed.
● Both the current in the wire XY and the magnetic field are reversed at the same time.
How many of these actions cause the direction of the force on the wire XY to be reversed?
0
1
2
3
A current-carrying coil in a magnetic field experiences a turning effect.
How can the turning effect be increased?
Increase the number of turns on the coil.
Reduce the size of the current.
Reverse the direction of the magnetic field.
Use thinner wire for the coil.
A student investigates electromagnetic induction. She has a bar magnet and a coil of wire that is connected to a sensitive ammeter.
Which movement does not cause a reading on the ammeter?
moving the coil to the right
moving both the magnet and the coil to the left at the same speed
moving both the magnet and the coil towards each other at the same speed
moving the magnet to the left
A steel magnet is placed inside a coil of wire. There is a large alternating current in the coil. The magnet is slowly moved out of the coil to position P.
How has the steel changed, if at all, when it reaches position P?
It has become a stronger magnet.
It has become demagnetised.
The poles have changed ends.
There has been no change.
An electric current is passed through a coil of wire.
Which diagram shows the shape of the magnetic field produced in the middle of the coil?
When a wire is moved upwards between the poles of a magnet, an electromotive force (e.m.f.) is induced across the ends of the wire.
Which device uses a moving wire to induce an e.m.f.?
a cathode-ray tube
a generator
a transformer
an electromagnet
An input voltage of 10 V is supplied to the primary coil of a transformer. An output voltage of 40 V is produced across the secondary coil.
The 10 V supply at the primary coil is now replaced with a 40 V supply.
What is the new output voltage across the secondary coil?
10 V
40 V
70 V
160 V
A metal wire is placed between the poles of a magnet.
The wire can be moved in each of three directions OP, QR and ST.
In which direction or directions must the wire be moved to induce an e.m.f. across the ends of the wire?
OP only
OP or ST
QR
ST only
Which graph shows how the output voltage varies with time for a simple a.c. generator?
A
B
C
D
The diagram shows a simple step-down transformer used to decrease a voltage.
Which part is the primary coil?
A
B
C
D
Which diagram represents the direction of the magnetic field around a straight wire carrying a current out of the page?
A
B
C
D
