1972-04-20 — Page 27

MEFERENCE LIBRARY

頁三第張七第二日七初月三年子壬厩复 WAH KIU YAT PO

郭日橋

21 APR 1972

【 四期星

日十二月四年二七九一圈公年一十六國民中

XXC)

From (1)

1972英文中學會考試題預習專欄

1972

寄院主編

化學科

(十五)

中文中學會考試題預習專欄

英文科(廿五)一許藩芳一

ENGLISH (25)

1972英文中學會考試題預習專欄

Comparing (1) and (3)

堅道英文書院主編

物理科

(廿五)

TYBACH (25)

45-)(a):

Fig. (2)

Potent- lone ver

10 compare two resistance by means of potentiometer, join the two resist- antes AB and CD in series, and pass a Current through them as shown in the diagrão. fing the length of potentio-

eter wire 1, corresponding to the 7.0. between A and B. Then remove the con nections from A and B to C and D and again find the corresponding length of potentiometer wire (11⁄2). Then by the

theory of potentiometer,

If the rea of eith

GD in ohms be known

can be found,

shat of the other.

very path such as ACFH, ABCH, etc. have the same resistance, hence the cur- rent must divide symmetrically as shown. Thus - of the current, that is, 2 amperes flows in AB, AC and au, and. P.D. between

4 and C 16 10 220 volts

For a similar reason P.D. betweez and E. 18 20 volts. Now BE, EC, CFA DC and CE are alike, and each carry

the whole current,

is 1 ampere

כיF

Herice.

One metoda to measure the rea287- ance of a galvanometer is to connect the circuit as shown. a high resistanc ris placed in series with a cell and

R1 la paral

a. moderate resistance with the galvanometer. in the battery arcuat

The current

ther

obtained

ne 2 resistances are then changed and Ry, which give the pace cure

sent in the galvanometer and hence the. Bame deflection

Then

ER2

Since the resistance of the cel always small comparison with and

intiacucing any sensible er:

between C and

1 x 1010

between A. and

20+ 10 50 vo

volta.

20

((0)

resistance.

current

8.33 on

The equivalent resistance of the ROSWOTK 18 8.33 chrs and the potential difference across 15 50 volta.

(461a) If the quantity measured in ZETO

while the scale reading of the instrument is not at ita zero point, then zero error 18 said to exist for that instrument. The proper correction to be applied to the scale reading 18. termed the zero error of the instrument

To determine the zero error of a potentiometer, apparatus are zonnected as shown in fig. 2. of last problem. after finding length sorresponding to P.D. between AB, CD, connections Le removed to A and D. and the length of wire corresponding to P.D. bet. veena and D (1,) is found

If there then R

13)

45

-30 200350*

20 x 450 - 30350

30 x 70 x 100

1500

The resistance of is 40 ohme

G)

onn

ad

(47)(a) In an experiment to find the

celaration due to gravity, the following results were obtained

Lansth(Om)

20 42 70, 102- 115 1:30.

L'ine of Vibra- JB4 0.65 0.84 0.94.

1.07 1.14

tions

Find the acceleration due to gai vity by graphical method,

Name two important precautions which must be taken in order to obtain good resulte in carrying out this experimente

Give one difference between the terms gass and weight.

mage of 10 k is hung 1790

1 spring balance attached to a lift. Descrive "ing explain how the reading.

ill be affected what

the balance

liftes moyang

with an

120cm/sec

ard acceleration of!

with a downward acceleration

uniform velocit

Take 6 ás 106/1

Archimed¢ë

CHEMISTRY (25)

2) Manufacture un sulphurio, sölu.

The production of sulphuric act

was first discoverad by heating green vitrach, Strongly until it decomposab so", ferrio ozide, sulphur diozide, auld Zuric acid and water'

2F690.78,0

A) Contact process.

The essential resulION BY KHAR MENS 688 18 the oxidation of gulphur dioxide to sulphur trioxide by atmospheric, ɔxygel using catalyst. Sulphur trioxide is" qiarolved, to form Aulphurio acid, The catalyst-used, is either playinum "black" ob vanadium pestozide. The reaction ia

otheralo and the heat-produced can bi gade use of in preheating the reaotants.

·Thus

Pt. or 0. 230

290 45.2 KOBL.

ir is purified from dust, arseni, chloride and water vapour by passing -successively through a "düst catcher avataan tower" and a "drying tower. 2 volumes of sulphur dioxide are then mixed with S volumes of purified air. The gaseous reactants are preheated by the heat sichanger, and exaction takes place to the converter once they are in contact with the catalyst. Sulphur triv ozida le led to the absorber.... Lank and Le dissolved in a solution of 98% sulph- uriò acid. The concentration of the acid in the tank le maintained at 98% by constant addition of water.

So

THE CONTACT PROCESS

(B) The lead chamber process for manu facturing sulphuric acid.

The essential reaction' involvØD.

the oxidation of sulphur dioxide to julphur trioxide by nitrogen aloxide

(a) Sulphur dioxide is obtained by

burning aron pyrites in. air.

1102

from

air.

Ammonia is oxidized to nitric oxide in the presence of platinum black.

50%

4NO

from

air

The nitric oxide subsequently reacts with oxygen in the air to form nitrogen dioxide.

from.

In the Lead chan

18 formed”

from

spra

fo) The nitric oxide produced in the

lead chamber can be reused.

Sulphuric acid produced by this

method reaches a concentration. of about 65%.

KMO

uniform rod AB, 24 a long, wel gam ing 24 kg, is supported at end B by a

flexcble cord and weighted, at end with 12 kg lead weight. The rod floats as shown with one-half its length submerged,

laud weight. The buoy out force on the san be neglected.

(a) Show in a digram all the forces

acting on the rod.

And the teneion in the cord.

10

Ar

Smrtn's retirement was)

Que to his rii health-

How the dog, could "faha

way puzzled most of us. The higher we climbed the Colder We felt

In to circumstances should you leave the castle without my permission.

at that time many a fi rezid

house,

My old trienu as well as neny new acquaintances o nine was waiting for me: at the airport.

The scenery was beautiful The man was changed with setting the house on fire The bandits atole all the Boney from the villagers, fam not independent of ms parents.

(a) permanently (b) thaws (c) bloomine

(d) vegetation (e) prehistori (f) refrigerato (g) mammoth (h) cliff

(1) excavated (j) ornament

The mountains surrounding the region produce extremes of temperature:

In summer, the temperature. may reach 95F..

A deep, permanently frozen. layer of earth-serves as a datural refrigerator.j

A mammoth was found. The prenistoric anima.in are dug up and eaten. av MiLd-dogs.

ne round a beetle encased in the ice

It is because the topsorb Sometimes thaws, to a

feptn or 31X reet.

The beetle, after its long Sleep of millions of years Noke up.

It was used as an. organep

Exercise 22

Rewrite the following sentences

directed??

The new car was Lifted out

of the pond and put back on the road by the farmers. (Start with "The farmers") The statements which were made by the witness were

unbelievable, (acart with "wha They worked until dark

(Use as long as

Fr 19 millions of yemi í since the world was "created by

Use "ago"):

Most of the studenty wela tired of the work.

(Start with "The work!) They went out of the house as soon as the rain stopped

Start with ""No sooner", The assistant manager took charge of the business when I was away

(se

during"

Many of the machines in the shop were made in England

(1st "machinery");

She was absent minded.

She could not see the talen

break into the house.

(Combine by using "too"

Take care of the pence and

the pounds wil) take car

of themselves.

(Use "1f").

B. Chinese to English

余謫居於黄遇王亭過见

白白鳥房,此吾故人陳慥 李常也何為而在此!」か子 亦矍然問余所以至此者,余告 262, 1973% Tip To £69 余宿其家。環堵蕭然而妻子 奴婢皆有自得之意余既聳

獨念方山子少時,使酒好剑, 用財如糞土,前十有九年,余在 岐让见方山子從两騎,扶二天 游西山鹊起大前,使骑逐而 射之,不瘦,方山子怨馬獨出, 發得之,因與余馬上論用與 及古今成败,自謂ㄧㄝ豪士、今

每日精悍之色,猶見於 眉間