Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Magnetism and Electromagnetism
293 practice questions
Topics covered
Practice questions
111–120 of 154 · Normal
Question 111
5 marks · Normal
Answer and see the solution →A solenoid is used as an electromagnet and is part of a moving-coil loudspeaker. The speaker is powered by an alternating current produced by a generator.
(a)[2 marks]Describe the magnetic field pattern produced around a solenoid when current flows through it.
(b)[2 marks]Explain why the core of the solenoid in an electromagnet should be made from iron and not steel.
(c)[1 mark]Explain briefly how the movement of a generator's coil produces an alternating current to power the speaker.
Question 112
5 marks · Normal
Answer and see the solution →A power station uses large generators and transformers to supply electrical energy to homes.
(a)[2 marks]Explain why the electricity generated by the power station must pass through step-up transformers before long-distance transmission.
(b)[2 marks]A step-up transformer has 120 turns on its primary coil and 2,880 turns on its secondary. If the input voltage is 11,000 V a.c., calculate the output voltage.
(c)[1 mark]Describe one danger associated with transmitting electricity at high voltages.
Question 113
2 marks · Normal
Answer and see the solution →A straight wire is moved rapidly across a uniform magnetic field. State what is induced in the wire and explain how you could increase the size of this effect.
Question 114
4 marks · Normal
Answer and see the solution →A student builds a device by pushing a bar magnet in and out of a coil of wire connected to a voltmeter.
(a)[2 marks]Explain why a voltage is seen on the voltmeter when the magnet moves.
(b)[2 marks]State two changes the student can make to increase the maximum voltage produced.
Question 115
3 marks · Normal
Answer and see the solution →A single straight wire is pulled at a speed of 0.5 m/s across a uniform magnetic field of strength 0.8 T. The length of the wire in the field is 20 cm. Calculate the maximum possible voltage induced across the ends of the wire.
Question 116
3 marks · Normal
Answer and see the solution →A generator in a power station uses coils of wire and a rotating magnet. Explain how this generator produces electricity. State TWO factors that affect the size of the voltage it produces.
Question 117
4 marks · Normal
Answer and see the solution →A small dynamo attached to a bicycle wheel generates electricity for the bike’s lights. The speed of the bicycle and the voltage output were recorded:
Speed (m/s) Voltage (V) 2.0 0.5 3.0 0.9 4.0 1.2 5.0 1.5 (a)[1 mark]Describe the trend shown by the data.
(b)[1 mark]If the cyclist increases her speed from 2.0 m/s to 5.0 m/s, by what factor does the voltage across the dynamo increase?
(c)[2 marks]Explain why increasing the speed of the bicycle causes the voltage to increase.
Question 118
4 marks · Normal
Answer and see the solution →A simple generator consists of a coil of wire rotating between the poles of a magnet.
(a)[2 marks]Draw a labelled diagram showing a coil rotating between two magnets.
(b)[2 marks]Describe what would happen to the induced voltage if the coil is rotated faster.
Question 119
3 marks · Normal
Answer and see the solution →Describe an experiment you could do to show how a voltage is induced in a coil when a magnet moves nearby.
(a)[1 mark]Name the apparatus you would use.
(b)[2 marks]Describe how you would carry out the experiment and what you would observe on the measuring instrument.
Question 120
1 mark · Normal
Answer and check →Which of these changes would NOT increase the voltage induced in a coil when a magnet moves nearby?
- A.Using more turns of wire in the coil
- B.Moving the magnet more slowly
- C.Using a stronger magnet
- D.Pushing the magnet in and out more rapidly