Cambridge IGCSE Physics Workbook 2nd Edition

Physics (Workbook Heather Kennett

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1 HODDER EDUCATION

Physics (Worl

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Cambridge IGCSE Physics Workbook

Extended

19 A high-speed e lectron beam enters a reg ion of un iform magnetic field, as shown .

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/1/

In which d irection are the electrons deflected?

Exam focu s Core 1 The diagram represents a relay when it is switched off.

What will cause the relay to switch on? .... --·---·-------·-------·----·---·----·--··--··-·- ·········-·-··--··--·----·-------·-------·-------·---···--··--··-·- ··-·-

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b What role does the soft iron core play in the n>lay?

/2/ What happens at X when the relay is switched on? ...

/2/ d Give a reason for using a relay. ..

/2/ [Totlll: lJ

Cambridge IGCSE Physics Workbook

Photocopying prohibited

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7 ELECTROMAGNETIC EFFECTS

2 An electromagnet, P, is used to lift some scrap iron. The table shows the maximum load that can be lifted when there are different currents in the electromagnet.

a

Draw a load/current graph with current along the x-axis and load along the y-axis.

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b Is your graph linear? .

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c

Whatcurrentisneededtoliftaloadof30N? ...

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d What maximum load could be lifted by a current of l.Z5A?

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A second electromagnet, Q has the same design as electromagnet P but has twice the number of turns on the coil. What advantages would electromagnet Q have over electromagnet P? .................................................................................................................................................................................................................... {1/

[Tota/:8]

Exten ded 3 The diagram shows a simple generator.

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Cambridge IGCSE Physics Workbook

Extended

a

Explain the function of the slip rings.

/1/ b Sketch the voltage output of the generator against time for one revolution of the coil.

/3/ c

\Viii the coil be horizontal or vertical when the induced voltage is a maximum?

/1/ d What type of current would there be in a circuit connected to the brushes?

11/ [Tota/:6]

4 In a d.c. electric motor a current-carrying coil attached to a corrunutator is mounted between the poles of a magnet. The coil experiences a couple.

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