1968-06-02 — Page 15

咸三第張四騁

日七初月五华甲戊更

WA KIU YAT PÔ

英中會考物理科答案(綠),陸永贼

Suggested Answers ▼

. PHYSICS

R.K. Certificate of Education. Examination. 1968

(a) Diagram of a Daniell Cell

i ca

viscel

(US)

· za rod, f» (HR)

Cu crystals]

[dil Hesa

·Porous par

depolarizer]

CMEQ sulf

When the copper (+vė plate) and zino { (-ve plate) are connected by a vize, the i

positive bydrogen ions of the sulphuric acid' passing through the porous pot, drift towarde the copper vessel. However, copper, sulphate solution is present outside the pot, and an avtion

E2+ Cuso - # 30

?

takes place which results in copper being deposited on the copper electrode instead of surrounded by hydrogen bubbles, and hence, polarization is overpone,'

The negative sulphate done of the electrolyte (H230,) drift- toward, the sinë pole, and gino"aulphate is formed, some sino is therefore used up winn the sel? do in use,

(b) When the battery is measured

in open circuit. The

voltmeter reads the e..f, of

the battery

E- 22 volts

When switch A le cloedd, the meter reads, the potential drop of the resistor 10 ohma.". V 2 volts,

A fall of 0.2 volts is observed, The "lost voltage" 0.2 volt drives purrent through the internal resistance of the cells, *

Let be the internal

resistance of the

sålls and I, the

{current in the

Carous t

Hila

0.2 x 10

off the Folsous †“

CHOTIL

To fa)

日二月六年八六九一路公车上

****** MRS. BENNETT

200

2001

200'

50

51 75

~25 50

1.

50

}

0.01667 kw-hr.

indused

Sample Answers,

H.K, Certificate of Education Examination (English}

1968

English Language II

I highly developed country domestio water consumption is greater than in a less advanced one because of the wide-spread use of automatió household machines and modern toilets and bathg Industry ussa vast quantities of water go an industrial country's consumption will be much greater than that of an underdeveloped ane. In addition modern industrial techniques often pause such savers pollution of water that it se impossible to re-use it. Water is also used in publio services which are more extensive in advanced nations.

Thus, sa the standard of laving ang industrisi advancement of more pountries mstę so will the world's consumption of vatos. Furthermore the rising world population wilə necessitate increased irrigation of land to produce more food.,

Because of the expense of transporting water the world's natural supply cannot be fully used, Therefore a new source of water must be found, probably through-distillation of gen water.

149 words,

Z. (a) (1) Marcel Lyme

(ii) close attention to small"detailr

(iii) an ordinary adventure film

(iv) being wrongly convięted

(v) receives a flogging

(vi) making us laugh

((vii) good will win in the end (viii) appreciative

(b) (1) hauled

(ii) vanquished '

(iii) adversitieg

(iv) fleeting

((v) ultimatel

(o). (1) The difference between the two filos

vas that the Captive" had the feeling of truth.

(11) The viewer reels that he is Hobson' (ii) when the hero shows that ka foole

compassion for Jom Bigga the viewerr also feel this,

we allail have learnt a lot about flyin didn't he?

I would have met you,

ought be?

she is

living (2) pitiful'.

(3) view

gone

environment}

Work

Stity of electricity

Jectrolysis, the.

ot substancës,) iberated, portional to theis

Verification of the" Law

Two voltametera, a copper and "a"silver voltaoster, ara connected in series with battery 10, koma tar and a ebeca tat,

RIES

LIBE

is used getting

"Bonds

have sent

have been

didn't see (did not say

(8). will be staying (9 ate

(10) made.

6. (1

or

(2) after (3).off

(4) to

} for

(a)

with

at

On

-11.831vwa TAJ

When both switches are OLOHUO,E60e;voi zmateri reada 1,8) volta

(c) In'parallel connection, the 'zwo-bulbs"give

brightness as their rated values,

In series connection,' the 25-watt bulb gives a brighter illumination than the 50-xa tt] jones. This may be explained ass-

Resistance of 25-watt bulb -

? B 25-7 40000

حمره

Realatanus of 50-wazz_bu) bi-,

Cha

25

40000

50

T-28

A

▲ suitable constant current'ia pagead (adjusted by the rheostat R) for a measured time and the manses of oopper and silver liberated: aza) waigħad,

01 and 2 respectivaly.

Quantity

Satomio WIT

copper

elver

valency:

chemical equivalent.

63.6

2

108

1.

31.8

108

1) Weight of hydrogen deposited'

7-

8

-0.125 gua

11) Mass of copper deposited

-31.6

8

31.6

K

हाथ

Brightness of lamp depende on_pèxer]

2

P. P

A

LB

2

parallel connection:

Energy consumed - 125 ✈ 50) watt-br

-

0.075 kv-fr.

----

to Baries, connection,

Energy consumed

B

fra, s mg = 31,8 108," the "accord "law":

of electrolysis is verified.

فن

•

&

Time of current passing - 3600 sec," mass of oxygen deposited 1 gm

Quantity Hydrogen

ma (gm)

atomic we

valency

Chemical

equivalent

Oxygen

Copper

1

2

16

63.6

2

2

31.6

Electrochemical equivalent of copper

2

0.00033 gm./coulomb

Since

zit

"2

tb

2 t

31,6

8 x 0.00033 x 3600 3.32 amp.

The current flowing is 3.32 amp.

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