第二剴張六第日四初月二年戌庚歷夏
WAH KIU YAT PO
報日僑翠
|18-4.
夏
三期星日一十月三年〇七九一曆公年九十五國民華中 育教僑華
For exhaust pump, the pressure after n strokes of the piston is given by
僑樂
P
3#%3
64 $%
where
5%$#$%$#$%$#$%$#8%$##$%$#$%$#$%$**
70英文中學會考試題預習專欄
堅道英文書院主編
物理科
(十九)
PHYSICS (19)
Solutions of Exer÷166 18
18-12
Volume coef. of a gas
70-273 per °C,
Yolune
where V is the increase in volumG
is the volume at 0°C or
7 is the temperature rise
Volume of coef, of a gaa
273 x 975
The Absolute Zero in degrees C 1# −273°C The Absolute Zero in degrees. ♬ is -(491 - 32)°F, } that is, −459 F.
18-2
1.29 gm of air at N.T.P. occupies 1000 010.
1 gm of air at N.T.P. occupies
1000 2:29
C.Ca
The pressure, 76 x 13.6 x 980 dynes per aq.om At N.F.P., the temp. is 273 K
器
76 x 13.6 x 980
1000
273
unito
Therefore, the gas cona tant
2.86 x 10 unita
10 gm of air at N.T.P. occupies
76 x 13.6 x 980 273
10000
x
2.88 x 10 units
10000
At 75 om. of mercury pressure and 27°C, 1000
of air at F.T.F. becomes
751 300
76 x 1000
273
1000 x 16
76
(But (1000 x
pressure weighs 1.29 gm
air at 27 C and 75 cm
(Therefore, 850 c.c. of air
at 27°C and, 75 ome
극동
273
pressure weighs
1000
0.985 gm.
This is the mass of
18-37
76 cm.
76-74.5
at 75
27.0
True pressure
- pressure in the space
13.5%om
vol. of air in the spac 90-74.5
15.5
- temp. at the moment.
288oK
The pressure inside 273+5278°K.
vol, of the air in the j
90 - 75.8
14.2 cm.
Applying the gas-law,
꼭꼭
금융
The trus atscepkerio preSSURE
than
1.55 cs
in 75.8 + 1.55
is the pressure of gas after a strokes
▼ is the volume of the vassal
(1000) 100
( §) - 100.
he effective volume of the pump.
nlog - - log 10-
***0.0792 25.3
Ans. It takes 26 strokas to reduce the pressSPO to sne-hundredth of its initial value.
Frercise 157)
Which of the following statements is correct? (4) Heat supplied to a substance will always
result in a rise in temperature,
(B) The higher the temperature in the sody, the
more heat energy it contains
(c) If two bodies of different temperatures are
brought into contact it does not necessarily followed that there in a heat transfor,
(D) Heat conduction does not involva a transrer of
energy.
(E) The temperature or a system san onange even
though there is no heat transferred to or from it.
12. The normal body temperature is 98.4°F. Itkán
converted into Celsius scale ad
22.4 degrees C. 26.9 degrass C
(0) 36.9 degrees C
(D) 54.4 degrees U
(E) 66,4 degrees ↑
A clinical thermometer has a short range of
aduation because --
it is measured inådegrees Fahrenheit marcury expands to a small extent only the fluctuation in the temperature of a patient is small
there is constriction in the TAGIDONOTer it is usually put in the mouth of a patient Two bodies are said to be at the sana temperature
(1) they possess the same amount of saurgy (B) they have the same specific heat. (C) they dissipate heat at the same rate
(D) they have the mace mace and in the same state
of matter
(3) there is se transfer of heat when they are in
contact with sach other
Water is naváz used as a liquid in the liquid-i: glase thermometer beca US S
I. water-adheres to the glass
II. pure unter should only be undu
III water expanda far tog suck than glass
IV. water expands from 4 G to 0.0
Statsmenta correct.
(4) I and II only
(3) II and III only
(C) II and IV only
(D) I, III and IV only
other combination
A rise of 40 degrass Centigrade in the name: AN Fise of
22.2 dog. F (B) 40.0 deg P 54-2 dag 7
(D) 72.0 deg P
(B) 104:0 deg. P
7. In a very cold day, the surface of a lake is
frosop to ice while the bottom of the lake is
(B)
The ratio of the coefficient of cubical expansion to that of linear expansion is approximately: (A) 1:2:
(B) 211,
(c) 191
(D) 113
:3 th
An iron red 1 meter in length and 1 am in diameter is heated from a temperature of 20°c to 100°c. As a result the diameter of the rod (A) diminishes because of the expansion of the
rod pr
(B) remains the same because heating gives an
expansive effect on its length only
(C) increases and then diminishes because the length of the rod is much longer than the diameter
8
increases, to some extent fog cannot be concluded, as the
© Cosxxicient or expansion or iron is not giver
10. The specifie heat of copper is 0.1 and the
specific beat of an alloy in 0.02. From this statement we understand that
(A) 0.02 caleries is needed to raise one gram
of copper one degree centigrade
(B) 0.1 B.Th.U. is needed to raise one gram of
copper one degree Fahrenheit
(c) 0.02 B.Th,U. is needed to raise one pound of
tha allar ons dazraa Fahranhast,
(D) equal amount of heat added will raise the
temperature of the two metals. 1 degree and 5 degress respectively
(5) copper has 5 times as much heat as the alloy
11. Water equivalent of a substance is the quantity
of water
(A) which has the same, specific heat as the
substanes
(B) which has the same specific gravity as the
substance
which has the same mess as the subetanos which has the same temperature as tho substanes
(B) which has the same thermal capacity as the
substance
12. The water equivalent, in grams, of a calprinster] having a mass of 60 gramu and a specific heat of 0.2.1#
(A) 12
(B) 30⋅
(C) 120
(D) 200
300
13. The following units measure the same physical
quentity except.
calories
British Thermal Units
watto.
(D) horseperez-nouro
(E) Joules
Equal volumes of gas at the same conditions of tanperature and pressure
(A) contafm the same number of molecules
(B) have the sane density
(C) have the same mana.
2) have
the same ionisation potential
have the name humidity
15. In order to double the volums of a given weight of oxygen at 50°C and at constant pressure, the temperatura must be raised to
(4) 100
(B) 273 0.
(C)323) (D):373
(B) 646°C
16. Compare the densities of a gas which changed from
a pressure of 30 in. of mercury at 15 to ar pressure of 33 inches of mercury at 59 F (A) 112.
(3) 211
(c) 11.04
(D) 11:52 (E) 1:1.1
A substanas required latent heat of fusion (A) change its state from liquië të solid (B) change its state from liquid to ges (C) change its state from gas to liquid (D) change its state from solid to liquid (E) change its state from solid to gas
18. Water always boils when
(A) its temperature reaches 100.0
(B) its vapour pressure is 1 gram per sq.co (C) ate saturated vapour pressure equals the
atmospheric pressmen
(D) its vapour pressure equals yo o ez meroury (E) 540 calories of heat is given to each gran
of water
19. 540 gram of ice at -100 is mixed with 540 gram
of water at 80°C. The final temperature of the nixture, in C, is (specific heat of ice is 0.5)
3) D
(0) 2.5
(D) 40
(E) 80
20. When ice is heated, it melta.
This is due to the fact that
(A) the molecules expand when heated.
(B) the molecules change their shape but not lay
#ize
(C) the molecules change their shape and size F (D) the molecules vibrate more violently (E) the molecules lose some
21. 1000 calories of heat are given
water at 54 Co
The mass of
··(4) 1.0 Team produced will be
(B) 4.2
(c) 5.4 m
(D) 10.0 gm
(B) nil as no steam is produced
22. The mean
10 gram of
mechanical equivalent of heat is
the amount of heat required to raise the temperature of the substance by one degree (B) an example of heat or energy conservation (0) a physical quantity which relates tuo
different physical quantities together
(D)
a conversion factor in converting a physical] quantity from one form to another
(E) numerically the same for any system or unsta The boiling point of water can be raised by
I. transporting it to a higher elevation II. dissolving salt in it.
III. adding heat to it at a more rapid rate.
IV, heating it in a closed container.
Statements correct
(A) I, II and III only
(B) I and III only
(C) II and IV only
(D) IV only
(E) Any other combination:
24. At zero degree centigrade,
water begins to freeze;
water molecules odase their motion water cannot exist in liquid state below this temperature
ice and water can erish in-equilibrium at
standard pressure.
(E) the daw point must be higher than this point