11 markeasy
Extended tier only
Which diagram shows the correct magnetic field pattern around a current-carrying solenoid?
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Co-ordinated Sciences (Double Award) — Physics
Electromagnetic Effects — Multiple-Choice Questions (Cambridge International IGCSE Science): Exam Questions
Exam code:097313 questions · 13 marks · ≈ 13 min
21 markeasy
Extended tier only
Which diagram correctly shows the magnetic field lines around a current-carrying wire if the current is directed out of the page?
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31 markeasy
Extended tier only
Which device uses a split ring commutator?
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d.c. motor
transformer
relay
a.c. generator
41 markeasy
Extended tier only
A simple d.c. electric motor is shown in the diagram.
Which of the following changes would make the coil turn more quickly?
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Reducing the strength of the magnetic field.
Reversing the direction of the current and swapping the magnetic poles.
Swapping the magnetic poles.
Increasing the current in the coil
51 markeasy
Extended tier only
The number of turns in the primary coil and secondary coil of a transformer is Np and Ns respectively.
Which of the following statements represents a step-up transformer?
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61 markmedium
Extended tier only
When a wire is moved through a magnetic field, an e.m.f. is induced in the wire.
Which of the following devices uses this effect?
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electric motor
electricity generator
photon accelerator
transformer
71 markmedium
Extended tier only
Which graph represents the output of a simple a.c. generator?
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81 markmedium
A magnet is pushed into a coil of wire connected to a centre-zero sensitive ammeter. The ammeter shows a negative reading, as shown in diagram 1.
The magnet is then held stationary inside the coil.
What does the ammeter read when the magnet is stationary, as shown in diagram 2?p
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a constant positive reading
a constant negative reading
a reading that slowly decreases to zero
zero
91 markhard
Extended tier only
Transformers are used to change the voltage of a power supply.
The diagram below shows a simple transformer.
If the input voltage is 48 V, what is the output voltage?
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2.4 V
9.6 V
240 V
667 V
101 markhard
Extended tier only
A current-carrying wire is placed between two magnetic poles as shown in the diagram below. It experiences an upwards force.
What is the orientation of the magnetic poles?
| Left magnet | Right magnet | |
|---|---|---|
| A | N | N |
| B | S | N |
| C | N | S |
| D | S | S |
Choose your answer
111 markhard
Extended tier only
A transformer is used to raise the voltage of electricity produced at a power station before it is transmitted in power lines.
The power station generates electricity at a voltage of 25 kV and a current of 4000 A. The step-up transformer increases the voltage to 400 kV.
Assume that the transformer is 100% efficient.
What current flows in the power lines?
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0.25 A
250 A
640 A
64 000 A
121 markhard
Extended tier only
A transformer has 1200 turns on its secondary coil and has an output voltage of 240 V.
If the input voltage is 12 V, how many turns are there on the primary coil?
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2
60
1200
24 000
131 markhard
Extended tier only
A current-carrying wire is placed into a magnetic field as shown in the diagram. The wire experiences a force.
In which direction does the force on the wire act?
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OP
PO
ST
QR