1974-01-25 — Page 18

真二第張五第二日三初月正年寅甲歷

釣橋等

1874 中學會考試題預習專欄 堅道書院主輪

物理科

solutions

PHYSICS (12)

21. Transverse waves are waves in

a) which the direction of vibrat-

lor is perpendicular to that of propagation. @•§•

A water wave due to a stone dropped in spreads horizontally the water particles vibrate vertically.

Longitudinal waves are waves in which the direction of vibrat÷ ions is parallel to that of propagation. e.g

Sound waves in air travel in the same direction as the vibrations,

b) (i) they differ in frequency

only.

-lude

I cycle-

(ii) they differ in

only

-1 cycle

¿cycle.

A

plitude

c) The same musical note played on two different instruments sounds different even when it has the same amplitude. It is because the number, frequency and amplitude of the overtones accompanying the main or fund- amental note of each of the

musical instruments are differ

ent

WAH KIU YAT PO

positive charges remains on the plate. Remove the finger and th the rod. The positive charges originally on the plate will spread over the metal rod and the leaf diverges.

The phenomenon of the accummu- lation of hydrogen bubles at the positive pole of a cell is called polarization.

ar

the defects wret

(1) The internal resistance of

the cell is increased beca- use the effective area of the positive pole in contact with the electrolyte is.

reduced.

(ii) The effective electromotive

force of the cell is reduced because the presence of the hydrogen bubbles produce. an electromotive force whicm tends to send a current through the cell in the

opposite direction to the current actually passing.

Problems for next week

a) Describe briefly three methods

of magnitising a knitting needle.

郭日僑筆

五期星

日五廿月一年四七九一瑟公年三十六國民中育教華備

Which of the peus would germinate From the conditions as set out in

III.

1974 中學入學試

Je must keep the city clean.

They set froe a turtle last-

night.

Lr. Poon is marking our

exercises.

4. Who built the Great Wall of

China?"

The life-guard has saved the

drowning girl.

(a), you would say that only those "A" would, wouldn't you? The reason is "B" lacks water,

"C" was too COLA,

"D" has no (oxygen as in boiling water, you have driven

out the oxygen and the layer of oil

prevents 0 in air from disolving in. the water,

For examination purpose, you would

have to describe this experiment stage by stage.

試題預習專欄

̇智慧出病社主講

(十二

英文科

SECTION A

(multiple choice)

2. There are two modes of germinatior I. Choose the best answer and namely epigeal eg. Castor Oil seedi- ing.

In epigeal germination, the cotyled- ous are raised above ground due to the elongation of the hypocotyle, turn green and become the first lea- ves of the plant But, in hypogeal germination, the cotyledons remain below ground, the food stored in them nourish the young seedling in Its growth until it has leaves of it own to make food. Then they shrivell ed up as their food is used up. Pre-reading Test:

VIII. Interdependence of Animals and

Plants.

The signs for the trigonometrical · ratios of when P is in the various quadranta are summaried is the following table.

quadrant

:008°

tan o

b) Describe the changes that are supposed to take place in the molecules of a steel bar when it is magnetised. Describe experiments to illust rate such changes as in b).

1st

2nd

3rd

4th

1) State Faraday's Laws of

electrolysis.

b) Draw a labelled diagram of the the apparatus and circuit “req- uired to electro-plate a brass tray

State the precautions necessar) for an even deposite of silver that will not drop off. – a) In the above experiment, the

current passed through the solution was 4 amp. The

voltmeter connected across the the cathode and anode gave a reading of 30 volts. The curr- ent was switched on for 10 hrs Calculate

(1) the mass of silver deposit (11) the

resistance of the

solution. (111) the cost of electrical

energy if it was supplied at a rate of 10% perk.w.H.

(e,o.e, of silver - 0.0011185/

columb)

1974中學會考試題預習專欄

Ban MBB IM

生物科(課程乙)(十二)卓唐邁借

General Angle

letter in the bracket.

the

1874 中學會考試題預習專欄 堅道書院主機

Example:

The man sells newspapers,

Newspapers (A, were sold B, have

been G. had been D. are sold E is sold) by the man

數學科(乙) (十二)女長波

(D)

The Governor risited Janpan în 1973.

· Japan (A, was visited B. is visited

C will be sited D. had been visited E, visited) by the Governor in 1973

2. They will build a new flyover....

A new flyover (A. will be built B. is built C. has been built

D. will build is being built)

by them.

3. We are watching television.

Television (A. is watched.

B. is watching 0 is being watched D. Was watched E. has watched)

by us.

4. John eats an apple everyday.

An apple ( is being eaten B. is eating C. has eaten Dis venten E. will be eaten)

by John everyday,

5. He has seen the film twice.

The film ( has seen B. saw C. will be seen D. is being seen. L. bas been seen) by him twice.

The general angle is an angla of any 6. Have you visited the zoo before? size (including negative angles),

(A. Had the zoo B. Has the zoo been

C. as the zoo being D. Is the

B. Will the zoo be) visited. by you before?

It should be noticed that the posit- ion OP can be arrived at by turning through any number of complete turna "plus the angle . Also, it is our convention that all positive angles are obtained by turning in an anticlockwias, direction from OX and negative angle by turning in a olockwise direction. from OX.

Furmulas for an angla reduced to an acute angla

1. min(1800)-sin e sin(90) -9)-003

Bin(180. -aine Bin(360

Bia(160° )=sin .0 sin(-)--in e

oos(180) ◊)-008 ◊ cos(90 † (0) -ain o oos(360 - 0)wcos D ́oos(270°-0)--sin 0 008(360 +9)=cos e cos(270 +0). sin 0

taní 180 (0)= -taż ◊ tan(130) 9) tän tan(3606). tan tan (300 + 0) tan tan(-9)--tan

Mathematics

tion to exercise-

•2mn+2

2mni

2m:1+2n

{m+2n+21

+2mn+2n

2n+2n

6. ()

7. The car knocked down some boys..

Some boys( A were knocked down

B. are knocked down C was knocked down D. knocked down E. had knocked down) by the car.

8. The police will arrest him.

He (A. is arrested B. will be arrested C. has been arrested D. is arresting E. was arrested)

by the police.

Dhe ought to obey her parents. Her parents (A. obyed B. obeys

G. ought to be obeyed

D. ought to be obey B. ought to obey) by her.

10. Mr. Lee is mending a puncture. A puncture (A is being pended

B. is mended C. mends D. will ba mended E. has been mended) by Mr. Lee.

2n

2.a.) L.H.S.

Bin

1+008: A

sin

Bin A1+coa A)

(1=008 £)(1+coa A)

sin+ COS A)

1-сов

ain A

R.E.S.

22

a) Using only a negatively charge charged rod, an electroscope can be positively charged by the process of induction. The negatively charged rod is. brought near the metal plate. Then the positive charges are attracted to the plate and the negative charges are repelled to the leaf, causing the lear to diverge. Touch the plate w with finger so that the elect- rone on the leat will pass through the body to earth and the leaf collapses. But the

Biology (12)

VII Germination

1.a.What conditions are necessary

for germination of seeds?

b. Describe an experiment to illus-

trate the above.

2. Distinguish between hypogeal and

epigeal germination.

Give an example for each.

we know, is the dorma- nt stage of life. When condition: are favourable they germinate and grow. The favourable externa: conditions necessary for germin- ation are:- NEED (1) Presence of water - which is

absorbed through the micropyle causing the tissues to become...” turgid, softening the teata and making it permeable to gases. (11)Presence of sufficient air as

oxygen is needed for aerobic respiration to liberate energy. for vital activities. (iii)Suitable temperature

there is

an optimum temperature for different geeds.

b. To illustrate that the above

conditions are necessary before germination takes place, look at. the apparatua as shown below.

Boaked peas

wet cotton wool

dry peas

dry cotton wool

soaked peas

Wet cotton wool. [placed in

refrigerator ]

cooled-boiled

water

aoaked peas

wet cotton wool

A,B and D were placed in Laboratory under Bane conditions of temperature. Cwas placed in the cool compart- ment of refrigerator.(not the freeze)

Solution

If COB A

and that A lies

between 270 and 360, find without using tables, the values of sin A and tan A.

Example 2 Simplify and in terms of tan(270° +A)• tan(189°-A) sin(270°-A)oos(130°+A)+cos(90°+A)sin(-A)

Solutions

Expression

COB Atan A).

sin A

sin

COA

Example 3 If A+B+C-180, Simplify

008 A sin C➡ sin(A+B) Cos(B+C) 008 A 008 C+ aos{ A+B) cos{B+C)

BolutionExpression-

Exercise 12

coa/sing-sing (006A COBACOBCI-COBCI-LOSA)

2008 A sin ◊ 2008 A coa C

tan C

1. If A be an angle lying between 180

270, and it 2 tan A-3, find, without using, tabbe, the values of

10sin A - 6008 A

Asin A + 3008 A

2. Find, without using tabbee, the valua

of oos(-300 } sin: 150°+aos(~315") sin (495°)+ taa 875" Bin 210°

3. Ir A+B+C-180°, Simplify

Sing sing + sin(B+C) Bină ocaÀ –

cos(B+C) sin(A+G}

II. Change these sentences into Passive

Voice-

He has eaten some oranges.

2. Tom flew a kite. yesterday.

3. When will they begin the match?

4. The servant put a vase on the table.

5. We have sung some songs,

III. Change these sentences into Active

Voice.

1. The city must be kept clean by

2. A turtle was set free by them last

night.

3. Our exercises are being marked by

Mr. Poon.

4. By whom was the Great Wall of China

built?

5. The drowning girl has been saved by

the life-guard.

ANSTERS

sin A(1+2′′co 1+008 A+C06 A-(1-cos

2

COGA+ 008 A

ein A(1+200S. COB A(2008 A+1,

tan A L.H.S.

Bin 0.

(1)+(2)008 +1 0-2.4

36

Angles greater than a rigid angle

The difinitions for sine, coaineane so on given in lesson 11 apply only to acute an (lea. For angia greater than 90o now definitions are required.

Let CX and OT be the coordinates axes with the same scale. Let P be the point (x,y),

OF-r and /POX-. Then we have the following dafinitions for the trigonome riosi ratios of o

SECTIONA

1. (A) 2. (A) 3. (C) 4. (D) 5. (B) 6. (B) 7. (A) - 8. (B) 9. (C) 10. (4).

sin

Y-coordinate of P

*

SECTION B:

II.

1. Some oranges have been eater.

by him.

x-coordinate of

сов

tan 0-

—coordinate of -coordinats

2. A Lite was flown by Tom

yesterday.

3. When will the match be begu

by them?

4. A vase was put on the table

by the servant

5. Some songs have been sung

by us.