NAME : CLASS - alinaimanarif.files.wordpress.com · UNIT FIZIK MRSM TUN GHAFAR BABA_7 5 Diagram 5.1 and Diagram 5.2 show identical copper rods placed on bare copper wires in the magnetic

NAME : _________________ CLASS : _________________ TEACHER’S NAME : _________________

CHAPTER 3-ELECTROMAGNETISM_2013

UNIT FIZIK MRSM TUN GHAFAR BABA_2

Section A

1 Diagram 1 shows a simple electric motor.

Diagram 1

(a) (i) Name the type of motor shown in the Diagram 1.

………………………………………………………………………………………………………...

[1 mark ]

(ii) What is the function of the part labeled X? ………………………………………………………………………………………………………...

[1 mark ]

(b) State one factor that affects the speed of rotation of the armature. ………………………………………………………………………………………………………...

[1 mark ]

(c) Name the rule used to determine the direction of the force.

………………………………………………………………………………………………

[1 mark ]

TOTAL

4 marks



2 Diagram 2 shows a transformer which changes the mains supply from 240 V to 9 V.

Diagram 2

(a) Name the type of transformer.

………………………………………………………………………………………………………...

[1 mark ]

(b) The electric current in the primary coil, Ip, and the secondary coil, Is, is 0.1 A and 2.0 A respectively.

(i) Calculate the efficiency of the transformer.

[2 marks ]

(ii) What is the power loss in the transformer?

[2 marks]

TOTAL

5 marks



3

Diagram 3 shows a magnet being used to induce a current in a coil.

Diagram 3

(a) (i) State Lenz's law. ………………………………………………………………………………………………………...

[1 mark ]

(ii) State the pole at X. ………………………………………………………………………………………………………...

[1 mark ]

(iii) On Diagram 3, mark the direction of the deflection of galvanometer when magnet moved

away the coil. [1 mark ]

(b) State three ways to increase the induced current in the solenoid.

………………………………………………………………………………………

………………………………………………………………………………………

……………………………………………………………………………………..

[3 marks]

TOTAL

6 marks



4 Diagram 4.1 shows an alternating current generator.

Diagram 4.1

(a) (i) Name the phenomenon used to produced an e.m.f in the coil.

………………………………………………………………………………………………………...

[1 mark ]

(ii) What is the effect on the current produced if the magnets are moved further apart from each other? Give a reason. ………………………………………………………………………………………………………

………………………………………………………………………………………………………

[2 marks ]

(b) Diagram 4.2 shows the graph of the output current against time.

Diagram 4.2



(i) State the value of the peak current. ………………………………………………………………………………………………………...

[1 mark ]

(ii) Calculate the frequency of the alternating current.

[2 marks ]

(c) What are the changes that need to be made to convert this generator to a direct current motor? ………………………………………………………………………………………………………...

[1 mark ]

TOTAL

7 marks



5 Diagram 5.1 and Diagram 5.2 show identical copper rods placed on bare copper wires in the magnetic field.

Diagram 5.1

Diagram 5.2 When the switch is on, the pointer of the ammeter deflects and the copper rod is moved to the final position as shown in the diagrams.

(a) What is the meaning of magnetic field? ………………………………………………………………………………………………………...

[1 mark ]

(b) Observe Diagram 5.1 and Diagram 5.2.

(i) Compare the deflection of the pointer of the ammeters. ………………………………………………………………………………………………………...

[1 mark ]



(ii) Compare the final position of the copper rods. ………………………………………………………………………………………………………...

[1 mark ]

(c) Relate the final position of the copper rod to the magnitude of electric current. ………………………………………………………………………………………………………...

[1 mark ]

(d) (i) Explain why the copper rods moved in the direction as shown in diagrams when the switch is on. ………………………………………………………………………………………………………

………………………………………………………………………………………………………

[2 marks ]

(ii) How can the magnitude of the force be increased? ………………………………………………………………………………………………………

………………………………………………………………………………………………………

[2 marks ]

TOTAL

8 marks



6 Diagram 6.1 shows an electricity transmission system from the power station to the consumers.

Diagram 6.1

(a) (i) What is the function of transformer? ………………………………………………………………………………………………………...

[1 mark ]

(ii) State the type of transformer X and transformer Y. Transformer X : …………………………………..

Transformer Y : …………………………………..

[2 marks ]

(iii) Practically a transformer is not 100% efficient. Some energy is lost in the transformer. List the factors that cause the energy loss in a transformer. ……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

[2 marks ]



(b) Diagram 6.2 shows a simple transformer used to light up a bulb labeled 24 V, 36 W.

Diagram 6.2

When the mains supply is switched on, the bulb is very dim.

(i) State two ways in which the brightness of the bulb can be increased without changing the voltage of the mains supply. ……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

[2 marks ]

(ii) Explain why the core is made from iron.

………………………………………………………………………………………………………...

[1 mark ]

TOTAL

8 marks



7 Diagram 7 shows a galvanometer with a resistance of 5 Ω and a full scale deflection of 5 mA.

Diagram 7.1 The galvanometer uses the interaction between the magnetic field of a permanent magnet and the magnetic field of an electromagnet to measure a small current. The coil of the galvanometer gets heated up quickly, thus affecting the reading shown by the pointer.

(a) What is meant by electromagnet? ………………………………………………………………………………………………………...

[1 mark ]

(b) Diagram 7.2 shows a concave magnet that use in galvanometer.

Diagram 7.2



Draw the pattern of magnetic field of concave magnet as shown on Diagram 7.2.

[2 marks ]

(c) Based on Diagram 7.1, state the suitable specifications for the coil and the core to make the galvanometer more efficient. Give the reason for the suitability of the aspects.

(i) Wire used for the coil ………………………………………………………………………………………………………...

Reason ………………………………………………………………………………………………………...

[2 marks ]

(ii) Core material ………………………………………………………………………………………........................

Reason ………………………………………………………………………………………………………...

[2 marks ]

(iii) Number of turns of the coil ………………………………………………………………………………………………………...

Reason ………………………………………………………………………………………………………...

[2 marks ]

(d) Underline the correct answer. The resistor should be connected (in series , in parallel) to the galvanometer

to enable it to produce a full-scale deflection when the current is 1 Ampere.

[1 mark ]

TOTAL

10 marks



ESSAY

1 Diagram 1.1 shows one insulated conductor which is moved downwards in a magnetic field. Diagram 1.2 shows three insulated conductors which are moved downwards in the magnetic field.

Diagram 1.1 Diagram 1.2

(a) What is meant by electromagnetic induction? [1 mark ]

(b) Using Diagram 1.1 and Diagram 1.2, compare,

(i) The number of conductor wires [1 mark ]

(ii) The deflection of the galvanometer pointer

[1 mark ]

(iii) Relate the number of conductor and the rate of cutting of magnetic flux [1 mark ]

(iv) Relate the rate of cutting of magnetic flux and the induced current

[1 mark ]

(v) Name the physics law involved [1 mark ]



(c) Diagram 1.3 shows a circuit breaker.

Diagram 1.3

Explain how the circuit breaker works.

[4 marks ]

(d) Diagram 1.4 shows the cross section of a moving coil microphone which converts one form of energy into another.

Diagram 1.4

Using an appropriate concept in physics, suggest and explain suitable modifications or ways to enable the microphone to detect sound effectively and generate bigger current based on the following aspect: (i) thickness of diaphragm (ii) strength of the material for diaphragm (iii) number of turns of coil (iv) diameter of the wire of coil (v) strength of magnet

[10 marks ]

TOTAL

20 marks



Paper 3 Section B

1. Diagram 1.1 shows a simple electromagnet using a coil of wires connecting to a dry cell is able to attract iron nails. Diagram 1.2 shows the number of iron nails attracted by the simple electromagnet increase when the number of dry cells are added.

Diagram 1.1 Diagram 1.2

Based on the observations on Diagram 1.1 and Diagram 1.2 and using your knowledge of the electromagnet:

(a) State one suitable inference. [1 mark ]

(b) State one suitable hypothesis. [1 mark ]

(c) With the use of apparatus such as a solenoid, direct current power supply, paper clips and other apparatus, describe an experiment to investigate the hypothesis stated in 1(b).

In your description, state clearly the following: (i) Aim of the experiment (ii) Variables in the experiment (iii) List of apparatus and materials (iv) Arrangement of the apparatus (v) The procedure of the experiment which include the method of controlling the

manipulated variable and the method of measuring the responding variable. (vi) The way you would tabulate the data (vii) The way you would analysis the data

[10 marks ]

TOTAL

12 marks

Documents

NAME : CLASS - alinaimanarif.files.wordpress.com · UNIT FIZIK MRSM TUN GHAFAR BABA_7 5 Diagram 5.1 and Diagram 5.2 show identical copper rods placed on bare copper wires in the magnetic