Name: ………………………………………………………… Class: ……………………….

PAPER 2, SECTION CNo. 1:You are asked to investigate the design and the characteristics of four alternating current generatorsshown in Table 8. Explain the suitability of each characteristic of the alternating current generators and determine the alternating current generator which can supply a large direct current to an electricalcomponent X shown in Diagram 8.

Generator

Density ofthe coil / kg m–3

Frequency ofrotation

Rectification circuit

G 9200 High

H 11600 Low

I 8960 High

J 10500 Low

[10 marks]Characteristics Explanation

Choose …………………

Because

…………………………………………………………

…………………………………………………………

……………

DECISION MAKING & PROBLEM SOLVING(QUANTITATIVE) SKILL

No. 2:As a research engineer in a factory, you are asked to investigate the characteristics of several substances in order to produce p-type or n-type to produce semiconductor diode.Table 9 shows the characteristics of five semiconductors P, Q, R, S and T.

Semiconductor

Electron

Valens of

intrinsicsemiconductor

Electron Valens

ofdoping substan

ce

Size of the doping atom

comparedwith the size of

the atom relative tointrinsic

semiconductor atom

P 5 2 Big

Q 4 5 Small

R 3 4 Small

S 5 2 Almost the same

T 4 3 Almost the same

Explain the suitability of the characteristics of the semiconductor P, Q, R, S and T to be used in theproduction of a semiconductor diode. Give reasons for your choice.Which type of intrinsic semiconductor below is the most suitable to be used. Give your reason for youranswer.

Type of intrinsic

semiconductor

Silicon

Germanium

[10 marks]

Characteristics Explanation

Module Pengayaan/Physics/Module 2

Name: ………………………………………………………… Class: ……………………….

Choose …………………

Because

…………………………………………………………

…………………………………………………………

…………………………………………………………

…………………………..

No. 3:As a researcher, you are assigned to investigate the characteristics of radioactive substances with different half-life to be used for the treatment of cancer. Diagram 12.1 shows radioactive rays directed towards the cancer cell in patient’s brain.Table 10 shows radioactive rays directed towards the cancer cells in a patient’s brain.

(a) What is meant by half-life?[1 mark]

(b) Sketch a graph of activity against time to illustrate the decay rate of a radioactive substance. Use your graph to explain how the half-life is determined.

[4 marks](c) Table 12.1 shows the properties

radioactive substances J, K, L and M.

(i) Based on Table 12.1, explain the suitable properties of the radioactive substances for use to kill cancer cells in patient’s brains.

(ii) Determine which radioactive substance is the most suitable for the treatment of cancer cells in a patient and give your reasons.

[10 marks](d) Diagram 12.2 shows a radioactive

decay series for Rn-222 nucleus to Pb-210.

(i) Describe what happens to a nucleus when it undergoes a radioactive decay.

(ii) Write an equation to represent the radioactive decay series of Rn-222 to Pb-210 in Diagram 12.2.

(iii) State the number of alpha particles and beta particles produced in the decay.

[5 marks]

Module Pengayaan/Physics/Module 2

Name: ………………………………………………………… Class: ……………………….

No. 4:Figure 4.1 shows circuits J,K , L, M and N each containing an ideal transformer. Diodes in the circuits are used for the purpose of rectification.

Key:Np = Number of turns in primary coilNs = Number of turns in secondary coil.

(i) What is meant by rectification ?

[1 mark]

(ii) Explain the working principle of a transformer. [4 marks]

(iii) You are asked to make a 12 V battery charger. Study the circuits , J ,K,L , M and N in Figure 4.1 and consider the following aspects :- type of transformer- ratio of number or turns in

primary coil to secondary coil- type of rectification- characteristic of output current.

[10 marks]

Explain the suitability of the above aspects and

hence, determine the most suitable circuit to

make the battery charger. [10

marks]

(b) Figure 4.2 shows a circuit consisting of a transformer , an ammeter and two light bulbs. The ammeter reading is 0.5 A and both light bulbs light up with normal brightness.

(c)

(i) What is the output of the transformer ?(ii) Calculate the efficiency of the

transformer?[5 marks]

[5 marks]

Module Pengayaan/Physics/Module 2