1965-05-21 — Page 15

有裝健康

【百三第四第

CITY

月四年白乙腊签

WAH KIU YAT PO

FALL

華僑教育

SECTION A

英中會考物理科

Explain what is mean by the "inoment" of a torce about a "pointh

State Archimedes' principle.

The wooden rod shown below is gatform, and weighs 140 gm,` It is first suspended, from two balances as shown in diagram then one balance is removed and the rod lowered into water until it is immersed as shown in diagrami 2.

(2

(iii)

Cardboar

Lal Bhet;

King:

The eptirusė: Aso

to the Maplaosa

WATET, AIDS at this.

sid polat at the" - substrzeć part of.

the god

Calculate the spring balance readings. "A" and "8"

Draw a diagram to show the forces acting on the rod when it

ls partly submerged in water as in diagram 2, and show the į, distances between these forces..

Calculate the spring balance reading "C", and the upthrussTM on the rod.

Calculate the specific gravity of the sodi

What to meant by the coefficient of sliding Kinetic) friction Describe a practical method of measuring the coefficient of kinètic

·Triction using a rectangular wooden block aliding on a wooden board. Mention any precautions which you think are necessary in order to obtain reasonably constant experimental resulte.

Assuming that all the surfaces of the block are the same in thebers what would be the affact an the value obtained for the coeficient friction if

11) the black were tuźnad on he wide during the Experiment}

so as to alter the area of contact with the honed ?

(2)

weights were added to the'kjunk soda to

三期星

日一廿月五年五六九一零公年四十五萬民富中

SECTION D.

Capp

Expukin what is meane by the statement that; "the latent heat of vaporisation of water to 540 calories per gm si normal atmospheric】

Briefly descrive an experiment to determine the fatent meat of ice, and state any precautions you consider to be important in this experiment.

(You need not draw the apparatus, and you need out explain how the latent heat is calculated from the readings taken.)

A simple laboratory experiment was performed in five steps

as shown in the scries of drawings below. Use the information; given to calculate the latent heat of steam

Stem

(1)

What conditions are required to produce resonance of sound, in a hollow container?

(ii) How can resonance of sound be recognised? (All) Gives

a practica every-Cay example of ause made of this effect.

Describe, with the aid of a suitable diagram, an experiment which uses a resonance tube, open al one end, and a tuning fork of known frequency, to measure the velocity of sound in air at room temperature..

Show how the required veloci, is calculated from.

the observations made.

The questions below require only brief descriptions, shortened wherever possible by the use of diagrams,

DO

at 100°c

{i}

(ii)

How can it be-shown that sound will not pass through a vacuum? How could it be shown that sound obays the same laws of reflection as light?.

(i) What conditions are necessary for two sound waves, travelling

the same direction, to cancel each other and give silence 2

395

The result chrained aliova leʻan lakécurare value for the Jaleni heat of steam because no precaution was taken to prevent aream). condensing in the exposed delivery tube and then trickling into the calorimeter. If the correct value of the latent hear of team is taken as 540 calories per gm calculate the mass of steam which must have condensed in the delivery sube during the (experiment,

The resistivity (or specific resistance) of the metal copper is 1.78 x 10 Ohm-cm. Explain what this statement means.

.

Describe the use of a metre bridge to determine the resistance of a gives length of iron wire, Draw a diagram of the circuit used, describe how the bridge was accurately balanced, and explain how the assistance of the iron wire could be found from the observations made.Ÿ

A steady current was made to pass through a'solution of copper sulphate as shown below. After 30 minutes, the cathode was found to have gained a mass of 1.485 gro.

25.Volt Battery

The coefficient of linear expansion of copper is 16.7 x 16" per deg. Cent. Explain what this statement means.

Describe with the aid of a suitable diagram, a simple laboratory method of measuring the coefficient of linear expansion of a metál soù. Shaw now the coefficient is calculated from the readings, taken.

The diagram below shows some water in a flash fitted with à capillary cube The flask is cooled slowly by bubbling air through ather which fills the beaker. The reading of the water meniscus in the capillary tube was then taken át fegular intervals as shown in the table below.

Maids

Boale Randing

75.54:23 2.3|2||18|2

14 16

(Minutes)

Cattan wool.

Ether.

Sulphate

Parellal copper #zestrodes, Aron of sich face

[Caissiate

The current flowing,

(ii)

The resistivity of the solution."

(1)

1本500 am

The quantity of heat produced in the solution exprässed in calories

Electro Chemical Equivalent of copper 3.3 ×30 coulomb.

Machanical Equivalent:25 Healine, z jouter per calorie,

Outline the molecular theory of magnetism and use it to, explain the magnetration and demagnetisation of iron and steel.

The diagrama below snosie be copied, thes completed and labelled au show how she galvanometer; resistance and terminals may be canoected to forim, in me CLEE), BÙ BUmetne, and to the other case;

Galvanometar..

Instrument ban.]

Terminal.

Kontact with the board ?

GIVE FESSORS for your BADÁME A

St. of block

(Answer the following questions, giving a belef, reason for dach:

Explain how bubbles of air at room temperature caused tha Tether to be cooled as they passed through it.

(la): What do you deduce was the temperature of the water aftag

-6-minutes 7.

(iii) :: What was the temperature of the water after 3 minutes?

(iv). After 2 minutes it was noticed that although the meniscus, kad 1 slapped moving, the stopper was being slowly pushed out of the flask. Why?

What is the purpoke of the cotton wool, sad was in crally ROGEGEASY 2:

GAONG PUBLIC LIBRA

A block of wood weighing 2 lb. tests on a wooden Inclined plany which makes an angle of 50 deg. with the horizontal. It is attached by a light string passing over a frictionless pulley to a pan and weights which together have a mass of 1 433.tb. Once started. the black just slides steadily up the plaie. Calculats (1) the kinetic confficient of friction between the block and the plans, (2) the acceleration of the black down the plane when the angle of the plans with the horisvatal is increased to 60 deg.

LAcceleration due to gravity c 32 teƒmoc*),

Explain what is meant by the serm "mechanical equivalent of heat”. An oil-burning ship's engine devsimps 3890 horse power at full speed. Calculate the fuel consumption in one hour If the efficiency of this sacine is 30%...

15. of the off used by the above engine; givas our 33,000 } British thermal units of hest on burning.

278 foot-pounds per B Th. U.

A very crude experimental attempt to measure the mechanical equivalent of heat was made as shown in the series of diagrame belów,

SECTION C

Explain the term "Principal focus" as it applies to a convar lans" and the term "Linear magnification".

UTAW

ray diagram to snow the action of a microscope, konsisting of" two lenses. Show clearly the formation of the intermediate and final images, the principal fort of the two lenses, and the paths of three rays of light, starting from the top of the object, and pasSANG) through the two lansas." (The "top" of your object should be a poin above the axis. ).

♬ concave spherical mirror with focal length 10 cm.. produces an image twice the height of the object. Une optical formulas to calculate the distances of the object and image from the mirror WHO ME)

îne vmage SUPERLER

"(ii) — the image is virtual"

arielty axplain the weign cODVERSIDE problems.

by Low resistance

#}}''n galvacometer having resistancu 6.5 enma... gives full scale deflection) (a) a current of 0.02 smps. Calcula=> the value of the resistance required to be consected to this galvanometer in order to convert ti Teig an ammeter giving fail sesto deflection for scurrent of 3.0 amp.

zane neri page or inta dous inner to naredily varierted and pinned in

y de la nouriame bavall;

Answer the following questione by completes the drawings:

Show the shape and direction of the magnetic field of force a the plane at right angles to, the long straight wire carrying an electric car rent

The lower end of the thin mets) rod just-dipe into the mercury in the dish," Show, the current direction and the direction in which? vod will move then the switch is closed,

(011) – The copper disc:16 rotated rapidly", "Szów the direction of the gurrons, if any, loduced to the coppur disc and in the circuit.

116] Show the direction of the current in the call induced by she

Satiing magnet as the N pole passes through the ring. Label the magnetic poles caused by this induced current in, the coil,

memave ilia pago and pin it Maida)

TONS CATWOr book.

Cocaine

-Plane perpendiculas to girə

Candidata's Mumber,?

Currend

Name a unit in which "luminous intensity"" för filuminaning powery (can be measured, and maine dny standard light source.

Copper dies)

Describe a simple photometer, and explain an expezimeni in which at is used to compare the luminous intensities filuminaung powers) of two lamps of the same colour,

aur

0.03%

Quick rotation to tube through 180 kasps the abot st the and of the tube

(Class

- Cork

Rotation stopped' in this position allows the shot to fall the length

of the tuber.

This process is sepented) 300 tlaws in quẩnh

annessalon, then the Sempu of the shot is

(1) The total energy "lost" by the falling obat

The beal gained by the shot.

mechanicsi equivalent of bear calculated from the “perimental results above.

Why does the abové experiment lead to an inaccurate result?: Explain what you consuler to be the most importaDS FABIONE. gamber than 1, 2, 3 su

Show now the luminous intensities of the twoj lanips are related to the measurements taken in the experiment.

Galculate me neight at which a 180 c. p. point source of, light must be hung above x desk in order that it should give an intensity of illumization of 5 foot candies at i point on the desk below the lamp.

If a plane mirror were to be placed horizontally i fs," above, this lamp, calculate the new intensity of illumination at the same point on the desk, assuming that the mirror velicts; all the light falling on it.

Explain why it is most likely that the actual intensity of silumination” on the desk will be greater than the calculated results, even assuming that the room is completely closed, and has only the one light source, which is the lampi

SFalling

agnes

twith ends

Page 15Page 16

真四第張四第

日一廿月四年已乙支

WAH KIU YAT PO

羅

准

·趙俊交安玉成

夏日談游泳

「粿實在是有意想不到 一的效果。

游泳不獨可以健身,而且保障水上

·街、黃燈、 身體健康录二岑安 個人均希望獲得的, 我們要求一生

阿夏季又基人 系統,肌肉蹺圄和特 主要是在殛會刻何體之道,那麼,游泳烈·岑安與李愛殛后

[們游泳的大好倖光,無機能5 可從游泳 弛和呼吸,待泳有 | 不少人包李澌案现假中發生良好的脫啊。了進步,動作便逐商

H,都金幣享受於海由於游泳是一到身 不感染力,爲在水 浴場中,稅時髦的一泡,當游泳時,可中有军力,可使到你

·猬朵妙法,乃是游泳 使身體上的钲一肌肉 長時間運動而不致点,仅毋須像貨沚河

因爲游泳是一種不受

:年齡限制的運動,可

·愛好者所激的。可均能够光份發起, 補疲勞,在水中運動 賚力,中年人以至老 是在著許多游泳兒 壯,伸縮能力與柔似所消耗的苦力,談 年人都可以與青年 當中,却没有一半人,他能抵受而來 任陸上運獄少, 一般游泳 Q

能修其正享受到游泳的緊張和推售,雲, 雖然游泳數小時也不 的劇俗,更不知道数 嘉縣為和薩背的肌肉 會感到疲係,反之,價 泳的好處爲何?

•游泳後澍肌肉戤 當庥裲鞬上做着同樣,不斷的游泳 游泳方地一發套 得宜,可以協助取的聯作,只要發分證,身體重最適當分, 優良的運動,除了鱨息高勢、加也會到疲勞陽分 椰果镔涵有峘地兩 够保障生命之外,點 促進血液術與增加,所以,一般攤疾定 個小降的游泳,這個 「於體格的鍛練,都有 力

,或小兒麻痺症,整人是不會發胖,游泳

「極大坤益的。大顯身 在學習游泳時是 生衚告該病的好處,除了增進像 產的神經組織, 要耐心和毅力的, 的病人對常游记, 康外,在心理上受益

華僑日報記者岑安與李愛蓮,昨日下

新娘午職於有利銀行出口部。附圖爲新人

案親友,藚客數百人 天成 新婚夫婦將於

十來,喜氣 明日在日本作畫

| 洋冽,黹非常1月旅行云,

麥爾諾手桃苗(新緻麗

音