頁二第張四第
日七初月三年西己歷變
WAH KIU YAT PO
郭日僑華
三期星
日三廿月四年九六九 公年八十五國民華中 育敦僑華
1969FU
-11-
一九六九中学入学試題預習員
物理科
(廿五)
·陸永熾
英文科 (廿五)
劉士俊
Test 25
47. Solution
PHYSICS (25)
(a) 4 substance which conducts current and
undergoes decomposition is called an
electrolyte. Electrolyte is commonly referred
to a solution of an electrolyta in water electrolyte solution, Solutions in water of noide, buses, and salts are electrolytes. Copper sulphate solution, dilute sulphurio acid, and ammonium chloride solution are electrolytes.
(b) conductor
(c)
copper
copper sulphate Bolution
(Cu50 + 120)
dilute sulphuric noid ..
(HS0 solution)
"annonium chlorids
solution (NH ̧Cl solution)-
carriers. of current
free electrona:... copper ions Ca Sulphate iona SO, Hydrogen ions E Hydrozyle ions OHTM
Hydrogen ions H*
Sulpazze zone SO
Hygrozyle ions
ON
ensonium ions NH
chlorine ions C1 hydrogen ions H hydroxyle ions OR”.
copper sulphate solution:
copper
(11) Cu
ions are discharged and deposited on the pathoda (K). At the anode (Á), copper ions go into solution in, preference to the discharge of either OH or 50 tons. As a result, the. cathode increases in weight while the anode slowly dissolves away.
(b) Faraday's Laws of electrolysis
The mass of any substance liberated during. electrolysis is proportional to the quantity of electricity passed through the electrolyte.
When the same quantity of electricity
passes through various electrolytes, the masses of different substances liberated are proportional to their chemical.
equivalente.
(b) Let n ga, be the mass of silver deposited
By Faraday's second law,
mass depositede.o.e.
0,3
0.00112
0.00033
12
0.33
current in the circuit
0.3
0.00033 I 15 x 60
If the word underlined rhymes with one of the words that follow it, write that word in the space.
you cannot find a word that rhymes with the underlined word write X.
Examplezi
двед book
tin
bean
seem
bean
duok
broke
box
rolled
Gold wrote
boat
ohurch march
touch
watch.
fetch catob
bag
10g
PLE
neck
buys
1188
rice
nice
(f) iaiter
better
redder
later
Trite the missing words in the spaces Tramples ↑ He isn't very tall, 15 he
It's cold to-day, isn't it?
a) It wasn't so cold yesterday.
No, it wasn't,
No. he lan Tea. it. 1B,
(b) They've been to Taibo before, haven't they?
Yes,
(c) You don't like chocolate,
No, I don't.
(d) He will be late,
Yes, he wil
(e) She doesn't go to school every day does she?
No,
3. Put a tick (/) against the word which best completes
the meaning of the sentence
on
Hr, Lee will arrive in
win
into f about
to
from
(b) She borrowed a book only:
the library.
in
by
of
.by.
(c) Our clothes are made into
cotton or WOOL
Electroplating is the process of coating one metal with another by means of electrolysis: The object to be plated is cleaned and placed. in a solution of a salt of the metal with which
it is to be plated. The object is connected
to the cathode, a bar of pure plating metal to the snode. Low-voltage D.C. is sent through the solution.
4
In the case of copper plating an article X, 1 is connected to the cathode and a piece of pure copper ia connected to the anode. The solution consists of copper sulphate (CuSO). The CuSO breaks up into positive (Cu **), 1ỗns. and negative (SO. 1ons. The positive ions are attracted to the cathode, gain two electrons and become neutral copper atoms. Thase atons then deposit as a fil on the surface of the article. The S0 ions migrate to the anode and combine with copper to form more copper sulphate in solution concentration of electrolyte remains constant
If the surface of the article ie thoroughly cleaned and a moderate current 18 passing in the circuit, a good deposite of copper will be formed. Too small a current will deposit very little copper Too large current will give a powdery deposit.
The
0.011.
on
(d) He entered his school at
1964.
across the coil
0.011 1-1.5 x 60
volta
by in
0.11 x 6
-1.5 volta.
(e) She invited me to
dinner
with
into
1.02 gm. of silver deposited in the silver voltaneter and the pid, across the coil is 1.5 volts.
(d) Atomic weight of copper 637/
Density of hydrogen at N.I.F. - 0.09 gm.// Since copper is divalent, the equivalent of copper is 63/2. /.
Let go, be the mass of hydrogen, By Faraday's second law,
The volume of this at N.T.P.
litres
63 0.09
at 77.5 on. and 15°0, the volume is calculated by gas law
with
(f) The box is full
gold.
by
into
with
(g) Milk 15 2004 of
your health,
at
for
未完轉入第四張第三頁)
If XI is a conductor carrying a current
between the poles N, S of a magnet.
Does XY move? Give reason for your answer.
63:
20.09
0.547 litres
(273 + 15)
273
760
775
lulated
water
Hydrogen
北
cathode
The volume of hydrogen collected will be 547
Questions for next week; 49.(a)(1) State a rule for detersining the direction
ofmovement of the wire AB. Namə two ways of increasing the force on the wize.
50%
(b) Describe the construction of the D.C.
Дупало.
State three factors which increase the e.m.f. of a generator.
How long will it take to heat 2 litres of water from 25 to 100°C in an electric kettle taking 5 anp. from a 220-volte eupply, and what would it cost at 15 cents per kilowatt-hour? (4.18 joules per cal.)
0000
(T) A small quantity of acid is added to
provide a vast number of extra ions to make the solution more highly conducting. (11) The nature of the electrode will
determine the ion that will be discharged. In the case of carbon electrodes have been used the products at cathode and ano remain hydrogen (two volumes) and oxygen (one volume) respectively..
48. (a) Cations are the positive ione which are being attracted towards the negative cathode. Anions are the negative ione. They are attracted towards the positive anode.
(11)
ㄌ
represents a cross-section of a wire leading current into the
paper. Draw
threads to represent the magnetic field due to N and 5 poles and ■ thick line to represent the motion caused by the field- combination.
(a) A N-pole is pushed towards the face of a
coil connected to a galvanometer G.
(1) Slow the direction of the induced current
flowing in 0.
(ii) State the law for the induction. (iii)' what difference occurs if the N-pole ie pushed very quickly towards the face of the coil?
(b) Give an explanation based on physical
principles for each of the following:- (1) A high voltage may be obtained from the secondary winding of an induction coil. (ii) A transformer will not operate if it is
connected to a storage battery. (iii) It is more economical to transmit A.G.
power than D, C,
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