賀二第張六第
日五初月二十年申戊夏
WAH KIU YAT PO
日橋
日僑華
三斯星
日二廿月一年九六九一腊公年八十五國民警中
请教備率
文中學會考試題預習
物理科
(+=)
陸永熾·
一九六九年中突中学會考試題預習
PHYSICS (12)
21, Solution
(a) (1) Useful application or solid siparis Zon
The tight fit metallic tyres on the wheels
of a locomotive is enabled by expansion. “
The difference of expansion of bimetallie strip is a very useful application in electric thermostats.
(ii) Useful application of 11ould expansion
The expansive effect of mercury or alcohol on heating indicates the temperature changes.
An uncompensated pendulum clock will lose time in warm days and gain, in cold weather. This is due to the change in length of the metallic rod which serves as a pandulum length. To compensate, a set of brass and iron rods is arranged so that the differential expansion of them will compensate each other. The pendulum length is therefore kept acnstant
(b) A flask with a tube inverted
as in the figure can be.” employed as a gas thermometer. When temperature rises, the water level in the tube descends. When temperature drops, the air contracts and water level ascends. The
(0)
rise and fall of water level.
determines the temperature
of the surrounding.
An air thermometer,
thus made has a very
serious handicap. Its readings are affected by the change in atmospheric pressure as well as temperature,
Thermonster corrections should be dealt
with in two stages:s
(1) Zero corrections
(2) Fundamental Interval correction The first stage is equivalent to sifting the scale bodily for zero correction, making equal corrections at all points of the scale. The second stage corrects the divisions not being exact degrees, This part of the correction is proportional to the reading.
Lero error + 1.5°C
Zero correction -1.5°C: Fundamenta Interval
(99.4-1.5):
97.9 divisions)
Fundamental Interval error Fundamental Interval correction
+2.1° in 100° +0.0210 per
true temperature.
(1) For a reading of 20°,
20 -1.5+ (20 x 0.021) - 20 - (1.5 - 0.12)
18.9°C
(11) For a reading of -10°.
~10 (1,5 0,21)
Fundamental interval
-11.7%
true temperature
Inis type of problem may be solved graphically The F.F. and B.P. corrections are plotted against their appropriate readings and the resulting two points are joined by a straight line. The graph, provides the total correction at any temperaturs.
(d) Since the brass rod is the shorter one and has,
the greater coefficient of expansion, the
(b)
required temperature must be above 15 Let the temperature be toC above.
For each rod
50.2(1+0.000012+)-(50.2-0.015)(1+0.000019£) (50,2+0.000602t)-(50.185+0.000954)
(0.000954 - 0.000602) = 0.015
t = 42.7
Ans Temperature at which both rods were
equal length » (42.7 • 151°C
57.700.
It means that 1 ft. of steel will increase by 0.000012 ft. when heated through 1 degree"
Thermom «7
Steel rod
Mer Micrometer Steam in
Steam
our
A length or metal rod, say 50 cm. long, is enclosed in a steam jacket as shown in figure. It is screwed in position of a micrometer screws The micrometer reading is recorded and also the temperature of the rod before steam is passed into the jacket.
The micrometer is then unscrewed: several tuma for expansion, Steam from a boiler is passed in for same minutes. The micrometer is once more adjusted and a new reading taken. The temperature of steam then is noted. Thus, h
Original length of rod — Initial temperature of rod m Final temperature of rode t 1st micrometer reading ***. 2nd micrometer reading y Increase in length Ax Rise in temperature a
sl
deg C
Chef, of linear expansion folt-t
(c) let & be the length between two points at 10°c
Gosf, of Linear expn, of steal is 0.000012 per
degree C.
Temp. difference, 4l - (20 - 10)oC
Actual length at 2000 - £20
l20 l'al
alst
• 0,000012 * 10)
500 x 1.0012
5 x 100.012 500.06
Ans. The actual lángth at 20°G 1s 500.06
18
The length of 76.52 cm. on the brasa correct only at 0°C. The brass scale expands when the temperature rises to 12, and the new length,, of 76.52 cm. of brass at 0°C is given by
76.5201 +0.000019 12)
76.52 x 1.000228
76.54
The actual height of the mercury colum. at 1290 18 76.54 co
Questions for next weekkt
23. (a) Distinguish between the coefficients or real
and apparent expansion of a liquid. Deduce an expression relating the density of a liquid, at différent temperatures, with a coefficient: of expansion.
A glass bottle, volume 50 c.c. at 0°., is filled with paraffin at 1590. What is the mass of the paraffin? The density of paraffin at 000, is 0.82 gm. per c.c.; the coefficient, of real expansion of paraffin for the range 0° to 15%. is 0.0009; and the coefficient of linear expansion of glass is 0.000009, both per deg.C. 24, (a) Describe, giving the theory, a method of
determining the real expansion of a liquid, if
solid which has a known coefficient of expansion and will sink in the liquid, is provided.
(b) A loaded glass bulb weighs 156.25 gm. in air,
57.50 gm. when immersed in a liquid at 15°C. and 58157 gm. when immersed at 5290. Calculate the mesh coefficient of real expansion of the liquid between 15°C, and 52°C. (Coefficient of Linear expansion of glass * 0,000009 per deg. C.)
(e) Ir the density of mercury at 0°C, is 13,596 gm. per c... What is its value at 60°C, if th toefficient of expansion of mercury is 0.000182 per deg. C.?
英文科 (十二)
王淑方
LESSON TWELVE
1969
CHAPTER TWO
GENERAL ENGLISH.
(D) THE ARTICLES (Continued)
EXERCISE 11
Fill in the blanks with 5', an
Iron za
(2) John is not
useful metal.
honourable man.
truth.
hour.
(3) Honest boys speak
(4) She returned after
school will close for the New Year Holiday.
The tourist guide knows way to the City Hall.
Ganges is sacred river.
(5)
(6)
(8) Japanese 1s
easy language.
(9) Which is (10)
longest river in the world?.
lion is
king of beasts.
EXERCISE 12
Insert the definite article, where necessary:
(1)
(2)
Pay over there is at Arithmetic.
supervisor inspected all
best in the class
(3) Jack as a student of
work and no
(4) All
(5)
(6) In
work carefully
architecture..
play makes Jack a dull boy.
sword.
pen is mightier than opinion of
shortest way to Japan.
Captain Smith this is the
(7) Duke of Windsor was once, King of England. (8) Which language do you know better,
English?
Nathan Road is one of
, Hong Kong.
(9)
(10) They always give
Christmas time.
(E) PUNCTUATION
The principal stops the full stop.
the semicolon (1)
the question mark
the dash (-
and the apostrophe
The Full. Stop..
The full stop is used:
D
German
busiest roads
servant: a" present at
in writing are:
the colon
-the comma ()
), the exclamation mark (1),
quotation marks (
At the end of all sentences except questions and exclamations,
e.g. We need your help. {Statement')
After
Stop him from doing that, (Command )
abbreviations such as B. Sc. Bachelor of v Science),' 0.5.A. (- United States of America).
(c) After initials,
རྒྱ་པ་ལ
¤.g. A. Ha Smith,
K. Y, Robinson
March)
(d) After contracted words
Feb. (February) Mar. memo« (» memorandum)
The comma is generally useds.
Be Colma
To record a list of things, etc.
At breakfast we had cakes, butter, some pieces of bread, orange juice, milk, and Lemonade,
(b) To mark off direct speech
"Tell me," he said, "at what time you
fell asleep last night."
"About three o'clock," I replied.
To mark off sentences or clauses where a pause is needed in reading, This is almost always the case when an adverb clause precedes a principal one.
Although it was snowing, we went out for a walk
»g.
If I can help you, I will help you.
To mark off words used in addressing a person (the Nominative of Address).
e.g. I should be very glad, Dennis, if you would
do this for me,
however".
mark off words or phrases like 'therefore! ,of course, for instance, etc. e.z. "You know, of course, the way to the general office; I needn't, therefore, to accompany.. you," said Dennis.
(1) In descriptive titles such as:
Elizabeth II, Queen of Great Britain
We saw Mr. Chang, your headmaster, this morning.
(g) To mark off phrases containing a participle when
a pause is required in reading:
The Colon
Dick, seeing that his friend was injured, ran quickly, to help him.
The Colon la used:
To separate two sentences of which the second explains more fully the meaning of the first. e.g. Jack's work is satisfactory: his answers
are thoughtful, his spelling is careful and his writing is good.
To take the place of clause of reason.
་ཆ་
conjunction introducing
g. Jim didn't go to school yesterday. He was
ill in bed. (= because he was.s.)
To introduce a number of items in a list, or to introduce a quotation.
My mother offered me the choice or any one of these for a birthday present a tele- vision sét, a bicycle, an electric toaster, a gramophone.”
Shakespeare salo: "netiner a porrower nor
lender be.":