IB PHYSICS TEST ON MAGNETISM AND ELECTROMAGNETISM

Transcription

1 DULWICHCOLLEGESHANGHAI NAME: TEACHER: IBPHYSICSTESTONMAGNETISMAND ELECTROMAGNETISM Time:40minutes INSTRUCTIONS AnswerALLthequestions.Writeyouranswersinthespacesprovidedinthis questionpaper.showallthestepsinanycalculationandstatetheunits. Calculatorsmaybeused. INFORMATION Thetotalmarkforthispaperis40.Themarksfortheindividualquestionsare showninroundbrackets:eg(3).

2 VL C &"0$#*$%,1+*"12%'$1$%,"1%+&&+2+,'$%$"-4.%#.%+%31/-.$,2+,#-.%,-%"12%*)+$$9 71+U1 ()+.W /+8.1, /1,+)%2-3 /+8.1, 4#21 _ Y"1%/-U1$%,"1%/1,+)%2-3%'&4+23$%+.3%,"1%U-),/1,12%(2#1L)0%$"-4$%+%$/+))%21+3#.89 M+N D"0%3-1$%,"1%U-),/1,12%$"-4%+%21+3#.8` MRN M(N C (-0%$,+.3#.8%+,%,"1%(+*W%-L%,"1%*)+$$%*-/&)+#.$%,"+,%"1%*+..-,%21+3%,"1%U-),/1,129 Y'881$,%,4-%4+0$%#.%4"#*"%,"1%,1+*"12%*-')3%'$1%,"1%$+/1%+&&+2+,'$%,-%&2-3'*1%+ (#8812%21+3#.8%-.%,"1%U-),/1,129 A% ;% M"N OV M='0-?*S*.-<Q1N A<!"#$$%$&'$'#(! IGCSE ELECTROMAGNETISM TEST

3 13. A wire carries a current. The wire is perpendicular to a magnetic field. A force acts on the wire and the wire moves. (a) This effect is used in a d.c. motor. (i) What does the abbreviation d.c. stand for? (ii) Apart from electric motors, name one other device which uses this effect. (b) Professor J A Fleming invented a rule to describe the directions involved in this effect. It is known as Fleming s left-hand rule. Complete the sentences. The first finger points in the direction of the... which is from... to.... The second finger points in the direction of the... which is from... to.... The thumb points in the direction of the.... (5) 18 *N26259A01828* IGCSE ELECTROMAGNETISM TEST

4 12. (a) When a wire carries a current perpendicular to a magnetic field it experiences a force. Name a rule that enables you to predict the direction of this force.... (b) A teacher set up a demonstration using a 6 V battery, two bar magnets and three metal rods as shown in the diagram. north pole of one bar magnet short metal rod south pole of the other bar magnet battery + Add an arrow to the diagram to show the direction of (i) the current in the short metal rod. Label it I. (ii) the magnetic field between the two poles. Label it M. (iii) the resulting force acting on the short metal rod. Label it F. (c) State two changes that would increase the force acting on the short metal rod *N31362A02028* IGCSE ELECTROMAGNETISM TEST

5 8. (a) Complete the sentence. Voltage is... across a copper coil when a... changes through the coil. (b) A transformer is used to change the size of an alternating voltage. Complete the equation for a transformer. input (primary) voltage output (secondary) voltage = (c) Transformers are used in the large-scale transmission of electrical energy. Choose phrases from the box to complete the sentences. You may use each phrase once, more than once or not at all. in the pylons in the transmission line in the turbine just after the transmission line just before the generator just before the transmission line (i) In the transmission system a step-up transformer must be located (ii) In the transmission system a step-down transformer must be located Q8 (Total 5 marks) *N31362A01328* 13 Turn over IGCSE ELECTROMAGNETISM TEST

6 5. A class uses a step-up transformer in a model transmission line. The transformer is shown below. The input voltage is 6 Va.c. and there are 20 primary turns. INPUT OUTPUT 6 Va.c. 20 turns of wire primary secondary (a) The output voltage is 24 Va.c. How many secondary turns does the transformer have? Number of turns =... (b) State how this transformer could be used as a step-down transformer (c) A student wants to use an input voltage of 60 Va.c. Why does the teacher tell him that this is not a good idea? (d) A step-up transformer is used just outside a power station to increase the voltage. State why the voltage is increased Q5 (Total 5 marks) *N34027A0936* 9 Turn over IGCSE ELECTROMAGNETISM TEST

7 9. The diagram shows the magnetic field between magnetic poles X and Y. X Y Use one word in each space to complete the sentences. (a) The straight, parallel, evenly-spaced lines show that the magnetic field pattern between X and Y is... (b) X is a... pole and Y is a... pole. (c) A particle moves through the magnetic field. An electromagnetic force acts on this particle. This shows that the particle must be... and that its motion is not... to the magnetic field. Q9 (Total 4 marks) 14 *N34027A01436* IGCSE ELECTROMAGNETISM TEST

8 5. (a) A student writes a list of descriptions of magnetic field lines. One of the boxes below has been completed to show that the description is correct. Complete two other boxes which have correct descriptions of magnetic field lines. Put a cross ( ) in the correct boxes. their direction is from North to South they show the shape of a magnetic field they only appear near hard magnetic materials they show attraction but not repulsion they can show the strength of a magnetic field (b) Two bar magnets are held near to each other on a horizontal surface. A magnetic field line is shown. N S S N (i) Draw two more magnetic field lines on the diagram. (ii) The magnets are released. In which direction will they move? (iii) Explain your answer to part (ii). 12 *N34944A01236* IGCSE ELECTROMAGNETISM TEST

9 (c) A magnetic field pattern is shown below. DULWICH COLLEGE SHANGHAI (i) Put a cross ( ) next to the correct words to complete the sentence. This pattern is produced by a flat circular coil a straight wire a solenoid when it is carrying a current. (ii) A student claims that this is a uniform magnetic field pattern. Do you agree? Explain your answer. Q5 (Total 8 marks) *N34944A01336* IGCSE ELECTROMAGNETISM TEST Turn over