1973-06-09 — Page 24

真四第六第日九初月五年丑癸腦裏

WAH KIU YAT PO

報日僑華

英中會考物理科答案

4-600/1.005 x 10-3

日九月六年三七九一层公年二十六國民華中 奇教備

六期星

humen eye is effected by an

alternation in the focal

length of the eye lens which

·堅道英文書院主答·

(0.4 x 10-32 x 8000__

is brought about by the ciliary muscles.

21

my

5. (a)

Physics

Suggested Questions (cont'd)

4. The vibration of an air column

in its fundamental mode is given by

4.02 x 103 kg/m. fundamental frequency of Y

(i) The circuit diagram for II is shown in fig. 2 and that for III is shown in fig

witaminy

3.

is

fy

50.2

522

(8284)

L

(

2/4.02 x 10

x600 1.005 x 10

≈ 300

Supply

(52)

where V is the velocity of sound in air and C is the end correction.

the

Plotting I against }, gradient of the straight line obtained is equal to

frequency of Tork

(f).

320

480

320

26 cm

17 cm

480

From the graph, the gradient is

27

- 27 x 320

760

tho feszes

V = 34560 cm/s = 345.6 m/s. The advantage of using two fork is that velocity of sound can be accurately determined by using a graphical method. The end-correction of the tube can be obtained similtaneously from the graph. If only one fork is used, the positions correspond- ing to higher harmonics must be determined and this is more. difficult than the determinat- ion of the fundamental mode. (b) Let L be the length of X, Y &

Z & T their tensions. The linear density of X

I (0.2 x 10-3)2 x L x 8000

1.005 x

10-3

Applying f =

300-

2

kg/m.

T

1.005 x 103

英中會考經濟及公共事務科答案

堅達英文書院生答·

H.K.C.E.E. (English), 1973

Suggested Answers

for

Economic & Public Affairs (Conventional Questions

3. (c) Outline the process by

which an Urban Councillor is elected to the Council and state the qualifications of the electors. What are the chief functions of the Urban Council and the Urban Services Depart- ment?

(i) The process by which an

Urban Councillor is elected to the Council: generally a candi- date is adopted by a political party, either the Reform Club or the Civic Association; he or she is then nominated: a propos -er, a seconder and a few supporters (the number accord- ing to the law at the time of election) file his or her name, address and occupation with the Returning Officer; the candi- date has to deposit a sum of

100.5 402

300 x 0.25

· 150 ha

The linear density of Z is

π(0.2 x 10-3)21 × 9000

mz-

- 1.131 x 103 kg/m.

The fundamental frequency of Z is

11 = 21/12/2

1.131 x 10-3 x 600/1.005 x 10-3

=300/0.8886

282.7 hz.

(ii) The wavelength of soundwave

produced by

X =

330 300

m

.1 m.

(iii) Radiowaves have the same

wavelength as the sound wave produced by X.

(c) (i)

зи 30 cm.

Applying

+

sign convention: real is positive.

+

TO 30

or

15

ст

7.5 cm

(ii) The pupil corresponds to the diaphram and the retina corresponds to the film. (iii) Since the student cannot

see distant objects clearly, he is short-sight. The image formed by the eye w is in front of the retina when the object distance is 15 m

To correct this defective vision concave (diverging) lens must be used.

(iv) A sharp image of the scene

being photographed is focused on the film by turning the screw mount of the lens to vary the distance between the lens and the film. the other hand, the focusing. of image on the retina of the

On

money which is forfected by the government should he or she

fail to be elected; his or her agent must ensure that the

total sum of money spent on

his or her election campaign. does not exceed a certain

maximum as laid down by the law otherwise his or her election is declared null and void, and he or she may be prosecuted for committing an offence against the Crown; a candidate may, if he or she chooses, to stand for election without being affiliated to any political party, in which case he or she becomes an independ- ent candidate.

(ii) the qualifications of the

electors in recent years have been amended so that more people can qualify as electors; but lunatics, felons under sentence, persons disqualified for corrupt practices at election are prohibited from voting; those eligible to vote include taxpayers (salaries tax and Business Profits Tax) for at least three of the six years of assessment. Justices

of the Peace; government servants occupying pensionabl posts; barristers and solicito:

9 in practice in Hong Kong and their clerks; people qualified professionally such as accountants and architects;

502

(ii) When only one heating coil

is working, power of the cooker

(200)2

50

80 watts

When the 2 corts are in series, the power of the cooker

(200)2

100

= 200 watts.

When the coils are in parallel, the power of the cooker

(200)2

25

1600 watts.

(iii) Power of the supply. 200 x 22 = 4400 W.

no.

of cookers with only one coil working at the same time

4400

. 800

to the nearest whole number. (iv) It is not advisable to

replace a blown fuse wire with copper wire because of the high melting point of the copperwire and the incorrect current capacity. b) To ensure a firm and event

deposit of silver on the curved surface of a short cylindrical mass rod, the rod must be cleaned first with sand paper and then wash- ed with distilled water. The brass rod is then placed symmetrically inside a cylind rical silver electrode. The brass rod forms the cathode & the cylindrical silver electrode forms the anode the voltameter. The vol meter is shown in fig 4.

those in possession of the Hong Kong Certificate of Education, Matriculation Certificates issued by the University of Hong Kong, or the Chinese University of Hong Kong or Diplomas issued by the Hong Kong Polytechnic; qualified ship officers; re- gistered teachers, nurses, doctors, dentists, surgeons, and pharmacists; full-time clergymen, priests, ministers, or monks and nuns; managing directors, journalists, photo- graphers, producers, announcers commentators of local news- papers or news agencies, or broadcasting stations.

es

(iii) The chief functions of the

Urban Council are: to pass by- laws concerning public health and sanitation; to supervise the management of government multi-storey car parks, public libraries, and the Hong Kong City Hall; to implement polici- on squatter clearance and resettlement of squatters through the work of the Resettlement Department; to implement policies on the main- tenance of hygiene at public places where food is prepared and sold, at slaughter-houses, parks and beaches through the work of the Urban Services Department; to seek government action on certain problems

}

(ii) Applying m - zIt

1.68 −1.12 x 10-6 x 103xIx 50 x 60

I 0.5 A.

(iii) The correction of the

ammeter reading is + 0.1 A.

6. (a)

(1) A beam of cathode rays.

consists of electrons.

(ii) Because a small amount of

gas will be a better conduct- or than when the tube is filled with the gas.

(iii) The bear of cathode rays

will hit the screen at a point on the OY axis. (iv) The beam of cathode rays.

will hit the screen at a point on the OX axis. (From Fleming's left hand

rule)

(v) To make the beam of cathode- rays hit the screen at the point P, the plates A & D must be charged negatively and plates B & C charged. positively.

(b) At balance,

(1)

60

0:30 ohms.

(ii). Let = resistivity of the material of the coil C, then...

30 = fx

157 7x3.14x0.01

P 30x3.14x0.01 ohm/cm

4x157

30 x 3.14 ohm/metro

157

0.15 ohm/metre.

(c)(i) If the coil C is heated up,

its resistance increases because metals have positive temperature coefficients. The point P is shifted to the right, ie. the length AP increases.

(11) No effect, if the galvano-

meter is shunted.

(111) No effect, if the internal

resistance of E increases. (iv) The coil which replaces C

has smaller resistance than C. The point B is shifted to the left, i.e. AP de- creases in length.

(v) The coil, which replaces C

has greater resistance than C, the point P is shifted. towards B, i.e. Ap increases in length.

brought up by the members; and to hold discussions on matters relevant to the terms and functions of the Urban Council through its various select committees.

(iv) The chief functions of the

Urban Services Department are: to enforce the by-laws passed by the Urban Council; to oper- ate the Hawker Control Force in the maintenance of public markets and hawker areas; to maintain a staff of street- sweepers responsible for the cleaning, collecting and dis- posing of refuse and nightsoil; to be responsible for pest. control; to supervise two abattoirs, one at Kennedy Town and one at Cheung Sha Wan; to control 11 public cemeteries and 3 public crematoria, public latrines, bath-hourses, parks, plavgrounds, tennis courts, Squash courts, beaches and swimming pools; to supervise the operation of 28 private cemeteries and one private crematorium; to provide 2 funer -al depots; and with the help of the Urban Council to promote organize and present a series of varied and extensive public entertainment programmes to a wide audience throughout the year.

END