Higher Still Multiple Choice
Mechanics 1.3 Pressure and Gases
1
1. A rectangular block of wood of mass 200 kg
has dimensions of 2 m by 1 m by 0.1 m. The
greatest pressure which the block can exert
when lying on a flat level surface is
A.
B.
C.
D.
E.
1 x 10 2 Pa
1 x 10 3 Pa
2 x 10 3 Pa
1 x 10 4 Pa
2 x 10 4 Pa
2
A solid cylinder of mass 20 kg has a
flat base of area 0.1 m 2 in contact
with the level table on which it
rests. The pressure exerted on the
table by the cylinder resting in the
position shown is
A. 2 Pa
20%
20%
B. 20 Pa
20%
C. 200 Pa
20%
D. 2000 Pa
20%
E. 20000 Pa
3
A vessel of cross-sectional
area A contains a liquid of
density  . At point X, a
distance h below the
surface, the pressure due
to the liquid is
A.  g / A
20%
20%
B.  h
20%
C. hg / A
20%
D.  h / g
20%
E.  hg
4
A flat-bottomed can of weight 5 N floats with
its bottom 0.10 m below the surface of a liquid
of density 1.0 x 10 3 kg m -3 . If it is to float at
the same depth in a liquid of density 1.2 x 10 3
kg m -3 , a weight of
20%
20%
20%
20%
20%
A.
B.
C.
D.
E.
1.0 N should be added
1.0 N should be removed
0.83 N should be added
0.83 N should be removed
0.60 N should be added
5
Five liquids of different density are contained
in separate, identical tubes. The density of each
liquid is given in the diagram. In which tube is
the pressure greatest at point X?
20%
20%
20%
20%
20%
A.
B.
C.
D.
E.
6
The glass beaker shown below contains a liquid of
density  and surface area A.
Which of the following is/are true about the
pressure, caused by the liquid, at depth d below the
surface?
I The pressure varies directly as the surface area A.
II The pressure varies directly as the liquid density  .
III The pressure varies inversely as the depth d.
A. I only
20%
20%
B. II only
20%
C. III only
20%
20%
D. I and II only
E. II and III only
7
The low density of gases is best explained by
20%
A. low speed of gas molecules
20%
B. wide spacing between gas molecules
20%
C. small diameter of gas molecules
20%
D. small mass of gas molecules
20%
E. large volume of gas molecules
8
When a substance changes from liquid to gas at
atmospheric pressure, its density changes by a
factor of
A.
20%
B.
20%
20%
C.
20%
D.
20%
E.
10 -5
10 -4
10 -3
10 -2
10 -1
9
Which of the following gives the approximate
spacing of molecules in solid, liquid and gaseous
states of water?
The molecular spacing in the solid is d.
20%
A.
20%
B.
C.
20%
D.
20%
E.
20%
Solid
Ice
d
d
d
d
d
Liquid
Water
Water
Vapour
d
10d
3d
d
3d
3d
10d
10d
d
1000d
10
A fixed mass of gas condenses at
atmospheric pressure to form a liquid. By
how much does its density increase and by
how much does the spacing between its
molecules decrease?
Approximate
increase in
density
A. 10 times
20%
B. 100 times
20%
20%
C. 1000 times
20%
D. 1000000 times
20%
E. 1000000 times
Approximate
decrease in
spacing between molecules
2 times
10 times
10 times
100 times
1000 times
11
A sample of oxygen gas at room temperature
and atmospheric pressure occupies a volume of
1 x 10 5 litres.
The temperature and pressure are now altered
until all the gas has been liquefied. The volume
of liquid oxygen produced is approximately
A. 1 x 10
20%
20%
B. 1 x 10
20%
C. 1 x 10
20%
D.
20%
E.
2
litres
3 litres
4 litres
1 x 10 5 litres
1 x 10 6 litres
12
At standard temperature and pressure,
approximately what volume of gaseous
carbon dioxide would be formed from 1 cm3
of solid carbon dioxide?
20%
A.
20%
B.
20%
C.
20%
D.
E.
20%
10 cm3
10 2 cm3
10 3 cm3
10 4 cm3
10 5 cm3
13
If p is the pressure of a gas and V is its volume,
in what unit could the quantity pV be measured?
20%
A. newton
B. watt
20%
C. newton metre
20%
-1
D. newton second
20%
E. joule
20%
14
In a gas, which physical quantity, averaged over
all the molecules, is directly proportional to the
Kelvin temperature of the gas?
20%
A. Mass
B. Speed
20%
C. Weight
20%
D. Momentum
20%
E. Kinetic Energy
20%
15
The Kelvin temperature of a gas varies directly
as
20%
A. the average momentum of the molecules
B. the average inertia of the molecules
20%
C. the average velocity of the molecules
20%
D. the average kinetic energy of the molecules
20%
E. the average potential energy of the molecules
20%
16
A temperature - 20°C is equivalent to
20%
A. 353 K
B. 293 K
20%
C. 253 K
20%
D. 20 K
20%
E. -253 K
20%
17
A liquid is heated from 17°C to 50°C. The
temperature rise, on the Kelvin scale is
20%
A. 33 K
B. 67 K
20%
C. 306 K
20%
D. 340 K
20%
E. 579 K
20%
18
Which of the following is not consistent with
the kinetic theory of an ideal gas?
A. The molecules occupy a small fraction of the
20%
20%
B.
C.
20%
D.
E.
20%
20%
volume of the container
The molecules collide inelastically
The temperature gives a measure of the
average kinetic energy of the molecules
The gas pressure is due to molecular collisions
The attractive forces between the molecules
are negligible.
19
The kinetic theory idea of temperature of a
body is that it
A. measures the degree of randomness of the
motion of the particles
B. is equal to the average momentum of the
20%
particles
C. is equal to the average speed of the particles
20%
D. is related to the average kinetic energy of the
20% particles
E. is equal to the total kinetic energy of the
20% particles.
20%
20
The pressure of a gas can be affected by
factors such as its mass, its density, its volume
and its temperature. Pressure is inversely
proportional to volume if
20%
A. mass alone is constant
20%
B. density alone is constant
C. temperature alone is constant
20%
D. mass and density alone are constant
20%
E. mass and temperature alone are constant.
20%
21
The pressure on a fixed mass of a gas is doubled
at the same time that its Kelvin temperature is
doubled. Its volume will now be
20%
A. one quarter as great
20%
B. half as great
C. the same as before
20%
D. twice as great
20%
E. four times as great.
20%
22
A sealed container of gas is heated from 300 K
to 600 K. What is the effect on the molecules
of the gas?
20%
A. the average speed is quadrupled
20%
B. the average kinetic energy is quadrupled
C. the average speed is doubled
20%
D. the average momentum is doubled
20%
E. the average kinetic energy is doubled
20%
23
During an experiment involving a fixed mass of
gas, the Kelvin temperature is trebled and the
volume is doubled. Due to these changes, the
pressure of the gas is
20%
A. 1/4
20%
B.
20%
C.
D.
20%
E.
20%
of its original value
2/ of its original value
3
1 1/2 times its original value
1 2/3 times its original value
6 times its original value.
24
The volume of a certain mass of air at 27°C is
3 m3 .
If the temperature is increased to 127°C
without changing the pressure, the new
volume of the air will be
20%
A.
20%
B.
20%
C.
D.
20%
E.
20%
2 1/4 m3
3 m3
4 m3
13 m3
15 m3.
25
The pressure-volume graph describes
the behaviour of a constant mass of
gas as it is heated. Which of the
diagrams below shows the
corresponding pressure-temperature
graph? (Where pressure (P) is in kPa
and temperature (T) is in K).
A.
20%
B.
20%
C.
20%
D.
20%
20%
E.
26
The temperature of a trapped gas is altered,
keeping the pressure constant. Which graph
correctly represents the variation of volume with
temperature?
20%
A.
20%
B.
20%
C.
D.
20%
E.
20%
27
The graph showing the relationship between
pressure and volume for a fixed mass of ideal gas
when the temperature is kept constant is
A.
20%
B.
20%
20%
C.
20%
D.
20%
E.
28
Which of the following graphs shows the
relationship between the volume of an enclosed
mass of ideal gas and its temperature when the
pressure is kept constant?
A.
B.
20%
C.
20%
D.
20%
20%
E.
20%
29
Which of the following graphs illustrates the
correct relationship between pressure P and
volume V for a fixed mass of gas at constant
temperature?
A.
20%
B.
20%
C.
20%
20%
D.
20%
E.
30
Gas in a cylinder is at room temperature and its
pressure is greater than atmospheric pressure.
Some of the gas is released into the atmosphere
and the cylinder is then resealed. What would a
graph of pressure (P)-volume (V) for the gas in
the cylinder look like while the gas is being
released?
A.
20%
B.
20%
C.
20%
20%
D.
20%
E.
31
Graphs X and Y show the pressure (P), volume (V) and
temperature (T) of a fixed mass of gas during an
experiment in which the gas starts with the conditions
shown at point 1 and undergoes changes to the conditions
shown at point 2.
Which of the following statements is/are correct?
I The gas expands according to Boyles Law (pressurevolume law)
II The gas is compressed at constant temperature
III The pressure decrease at constant temperature.
A. I only
20%
20%
B. III only
20%
C. I and II only
20%
D. I and III only
20%
E. II and III only
32
A diver’s air cylinder has a capacity of 0.06 m3 .
4.0 m3 of air with a density of 1.44 kg m-3 is
compressed into it.
What is the density of the air in the cylinder?
20%
A. 0.02 kg m
-3
20%
B. 0.17 kg m
-3
C. 5.76 kg m
20%
-3
D. 6.00 kg m
20%
-3
E. 96.0 kg m
20%
-3
33
The pressure gauge on an oxygen cylinder of
capacity 0.1 m3 reads 1.0 x 10 7 Pa. The density of
oxygen at atmospheric pressure (1.0 x 10 7 Pa) is
1.4 kg m-3 .
Assuming that the temperature remains constant,
what is the density of the oxygen in the cylinder?
-3
20%
A. 0.14 kg m
-3
B. 1.4 kg m
20%
C. 14 kg m
20%
-3
D. 140 kg m
20%
-3
E. 1400 kg m
20%
-3
34
After a car has been parked in the sun for some
time, it is found that the pressure in the tyres
has increased. This is because
A. the volume occupied by the air molecules in the
20%
B.
20%
C.
20%
D.
20%
E.
20%
tyres has increased
the force produced by the air molecules in the
tyres acts over a smaller area
the average spacing between the air molecules
in the tyres has increased
the increased temperature has made the air
molecules in the tyres expand
the air molecules in the tyres are moving with
greater kinetic energy
35
Air is enclosed in a cylinder by a gas- tight piston
which can move freely in the cylinder. The crosssectional area of the piston is 3 x 10-3 m2. When the
atmospheric pressure is 100 kPa, the piston, when
no force acts, settles 8 cm from the end of the
cylinder (fig. 1). It is then slowly pulled out until it
is 16 cm from the end of the cylinder (fig. 2).
Assuming no change in temperature, the force F
required to hold the piston in this new position is
20%
A. 150 N
20%
B. 200 N
C. 300 N
20%
D. 450 N
20%
E. 600 N
20%
36
Flasks X, Y and Z have the same volumes. Y
contains air at a pressure of 600 kPa. X and Z
have been evacuated and the taps are closed.
Tap 1 is now opened, followed a short time later
by Tap 2. Assuming that the temperature
changes are negligible, the pressures in kPa in
flask Y become respectively
Tap 1 open
20%A.
600
20%B.
600
300
20%C.
300
20%D.
300
20%E.
Tap 1 and 2 open
300
200
200
150
100
37
A rectangular box of mass 10 kg is lying on a flat
surface on a planet where the gravitational field
strength is 4 N kg -1 . The base of the box measures
4 m by 2 m.
Which of the following statements is/are correct ?
I The weight of the box is 100 N.
II The weight of the box is 40 N.
III The pressure which the box exerts on the flat
surface is 5 Pa.
20%
A. I only
20%
B. II only
C. III only
20%
D. I and III only
20%
E. II and III only
20%
38
The end of a bicycle pump is sealed with a small rubber
stopper. The air in chamber C is now trapped. The plunger is
then pushed in slowly, causing the air in the chamber C to be
compressed. As a result of this, the pressure of the air
increases . Which of the following explain(s) why the
pressure increases, assuming that the temperature remains
constant?
I The air molecules increase their average speed .
II The air molecules are colliding more often with the walls
of the chamber.
III Each air molecule is striking the walls of the chamber
with greater force.
A. II only
20%
B. III only
20%
20%
C. I and II only
20%
D. I and III only
20%
E. E I, II and III
39
An aircraft cruises at an altitude at which
the air pressure is 0.4 x 10 5 Pa. The inside
of the aircraft cabin is maintained at a
pressure of 1.0 x 10 5 Pa. The area of an
external cabin door is 2 m 2 .
What is the outward force produced on this
door by the pressures stated?
20%A. 0.3 x 10
20%B.
20%C.
20%D.
20%E.
5
N
0.7 x 10 5 N
1.2 x 10 5 N
2.0 x 10 5 N
2.8 x 10 5 N
40
A small metal block is suspended from a spring
balance at a depth h below the surface of a liquid in
a large beaker. Which of the following statements
is/are true?
I The reading on the spring balance depends on the
density of the liquid in the beaker.
II The reading on the spring balance is equal to the
upthrust of the liquid on the metal block.
III The reading on the spring balance will increase
as the depth h is increased.
A.
20%
B.
20%
20%
C.
20%
D.
20%
E.
I only
II only
III only
I and II only
I and III only
41
Which of the following gives the approximate
relative spacings of molecules in ice, water and
water vapour?
Molecular
spacing in
ice/units
20%
A.
1
20%
B.
1
C.
1
20%
D.
1
20%
E.
3
20%
Molecular
spacing in
water / units
1
3
3
10
1
Molecular
spacing in water
vapour/ units
10
1
3
10
10
42
Which pair of graphs correctly shows how the
pressure produced by a liquid depends on the
depth and the density of the liquid?
20%
A.
20%
B.
C.
20%
D.
20%
E.
20%
43
A spacecraft of mass 1200 kg has landed on a
planet where the gravitational field strength is
5 N kg-l . The spacecraft rests on three pads,
each of contact area 0.5 m 2 .
The pressure exerted by these three pads on
the surface of the planet is
20%
A. 8.0 x 10
20%
B.
C.
20%
D.
20%
E.
20%
2
Pa
4.0 x 10 3 Pa
7.8 x 10 3 Pa
9.0 x 10 3 Pa
1.2 x 10 4 Pa.
44
A girl wrote the following statements in her notebook.
I The pressure of a fixed mass of gas varies inversely as
its volume, provided the temperature of the gas remains
constant.
II The pressure of a fixed mass of gas varies directly as
its kelvin temperature, provided the volume of the gas
remains constant.
III A temperature change of 20°C in a gas is the same as a
temperature change of 293 K.
Which of the above statements is/are correct?
20%
A. I only
20%
B. II only
C. III only
20%
D. I and II only
20%
E. II and III only
20%
45
The pressure-volume graph below
describes the behaviour of a
constant mass of gas when it is
heated.
Which of the following shows the
corresponding pressuretemperature graph?
20%
A.
20%
B.
C.
20%
D.
20%
E.
20%
46
On a cold morning, a motorist checks the pressure of the
air in one of her car tyres. It is found to be 3.0 x 10 5 Pa at
a temperature of 2 °C. After a long run on a motorway, the
temperature of the air in the tyre rises to 57 °C. The
volume of the air in the tyre remains constant and no air
escapes. Which row in the following table gives the correct
value of the final pressure of the air in the tyre and a
correct statement about the final density of the air in the
tyre compared to the initial density?
Final pressure
20%
A. 8.6 x 10
B.
20%
C.
20%
D.
20%
E.
20%
6
Pa
8.6 x 10 6 Pa
8.6 x 10 6 Pa
3.6 x 10 6 Pa
3.6 x 10 5 Pa
Final density of air of air
greater
same
less
same
less
47