Deck 14: Gases and Plasmas

Question 1

At normal atmospheric pressure and temperature, 1 cubic meter of air has a mass of about

A)1.00 kg.
B)1.25 kg.
C)2.00 kg.
D)2.25 kg.

Answer 1

1.25 kg.

Question 2

Consider two mercury barometers, one with twice the cross-sectional area of the other. Neglecting capillarity, compared with the wider tube, mercury in the smaller tube will rise

A)to the same height.
B)twice as high.
C)four times as high.
D)more than four times as high.
E)none of the above

Answer 2

to the same height.

Question 3

Atmospheric molecules do not fly off into outer space due to

A)their chaotic speeds.
B)their relatively low densities.
C)Earth gravitation.
D)cohesive forces.

Answer 3

Earth gravitation.

Question 4

In drinking soda or water through a straw, we make use of

A)capillary action.
B)surface tension.
C)atmospheric pressure.
D)Bernoulli's principle.
E)none of the above

Question 5

The energy source responsible for molecular motions in Earth's atmosphere is

A)their own natural kinetic energy.
B)pressure caused by the weight of air.
C)atmospheric tides.
D)the Sun.

Question 6

About what percentage of molecules in the air make up the atmosphere below a 6-kilometer altitude?

A)20%
B)30%
C)40%
D)50%
E)more than 50%

Question 7

The air in your classroom has

A)mass.
B)weight.
C)energy.
D)all of the above
E)none of the above

Question 8

What approximate weight of air is in a column 1-cm² in cross section that extends from sea level to the top of the atmosphere?

A)0.01 N
B)10 N
C)100 N
D)1000 N

Question 9

Compared to the ocean, Earth's atmosphere is different in that

A)its density varies with depth.
B)it has a less-distinct surface.
C)molecules are more greatly spaced.
D)all of the above
E)none of the above

Question 10

Marshmallows in a vacuum become

A)larger.
B)smaller.
C)flat.
D)a hollow shell.
E)none of the above

Question 11

The weight of air in a column 1-m² in cross section that extends from sea level to the top of the atmosphere is

A)101 N.
B)10,100 N.
C)101,000 N.
D)101,000,000 N.

Question 12

When a suction cup sticks to a wall it is

A)pulled to the wall by the vacuum.
B)pushed to the wall by the atmosphere.
C)both of these
D)neither of these

Question 13

Alcohol is less dense than water. If alcohol is used to make a barometer at normal atmospheric pressure, the height of the alcohol column would be

A)less than 10.3 m.
B)10.3 m.
C)more than 10.3 m.

Question 14

About how high can water at sea level be theoretically lifted by a vacuum pump?

A)less than 10.3 m
B)10.3 m
C)more than 10.3 m

Question 15

A column that extends from sea level to the top of the atmosphere contains a certain mass of air. If the column instead contained the same mass of mercury, its height would be about

A)3/4 meter.
B)10.3 meters.
C)5.6 kilometers.
D)none of the above

Question 16

It would be easier to pull the evacuated Magdeburg hemispheres apart if they were

A)held upside down.
B)at sea level.
C)20 km beneath the ocean surface.
D)20 km above the ocean surface.
E)none of the above

Question 17

Two vertical tubes of equal cross-sectional areas are filled with liquids to heights producing atmospheric pressure at their bottoms. One liquid is water and the other is mercury. Both liquids have equal

A)volumes.
B)densities.
C)weights.
D)viscosity.
E)none of the above

Question 18

A column that extends from sea level to the top of the atmosphere contains a certain mass of air. If the column instead contained the same mass of water, its height would be about

A)3/4 meter.
B)10.3 meters.
C)5.6 kilometers.
D)none of the above

Question 19

Approximately how much air is in a column 1-cm² in cross section that extends from sea level to the top of the atmosphere?

A)1 gram
B)1 kg
C)10 kg
D)100 kg

Question 20

Atmospheric pressure is caused by the

A)density of the atmosphere.
B)weight of the atmosphere.
C)temperature of the atmosphere.
D)solar energy on the atmosphere.

Question 21

When a gas in a container expands to twice its volume, its density

A)halves.
B)doubles.
C)quadruples.
D)remains the same.

Question 22

The buoyant force on a one-ton blimp hovering in air is

A)zero.
B)one ton.
C)less than one ton.
D)more than one ton.

Question 23

When a gas in a container is squeezed to half its volume, its density

A)halves.
B)doubles.
C)quadruples.
D)remains the same.

Question 24

As a high-altitude balloon sinks lower into the atmosphere, it undergoes a decrease in

A)volume.
B)density.
C)weight.
D)mass.
E)none of the above

Question 25

The buoyant force of the atmosphere on a body is equal to the

A)weight of air displaced.
B)volume of air displaced.
C)mass of the air displaced.
D)all of the above
E)none of the above

Question 26

The mass of air inside an average mid-size automobile is about

A)0.2 kg.
B)2 kg.
C)20 kg.
D)200 kg.
E)2000 kg.

Question 27

The weight of air in a bathtub (about 1/3 cubic meter)is about the same as the weight of

A)a pea.
B)an egg.
C)a small apple.
D)a pound of butter.
E)a 10-pound sack of potatoes.

Question 28

Compared with air pressure on the outside, air pressure inside an inflated stretched balloon is

A)less.
B)equal.
C)greater.
D)need more information

Question 29

The depth to which an inverted drinking glass must be pushed beneath the water surface to squeeze the enclosed air to half its volume is

A)76 cm.
B)10.3 m.
C)14.7 m.
D)20.6 m.
E)29.4 m.

Question 30

While Debbie Diver holds her breath and swims deeper and deeper beneath the water's surface, her density

A)increases.
B)decreases.
C)remains the same.

Question 31

If one of the pair of Magdeburg hemispheres were fastened to a strong tree, the force needed by a single party to pull them apart would be

A)half as much.
B)the same.
C)twice as much.
D)none of the above

Question 32

When boarding an airplane you bring a bag of chips. While in flight the bag puffs up, because

A)air pressure in the air-tight bag is greater than cabin air pressure.
B)suction is occurring.
C)air pressure is affected by the Bernoulli principle.
D)all the above
E)none of the above

Question 33

A scuba diver losing her air supply while far beneath the water surface is advised when ascending to

A)hold air in her lungs.
B)allow air to escape her lungs.
C)panic.

Question 34

A bubble of air released from the bottom of a lake

A)rises to the top at constant volume.
B)becomes smaller as it rises.
C)becomes larger as it rises.
D)alternately expands and contracts as it rises.
E)none of the above

Question 35

A swimmer cannot snorkel more than a meter deep because air

A)in the lungs cannot easily be expelled.
B)tends to liquefy in the snorkel tube.
C)is buoyed up leaving the swimmer breathless.
D)at the surface will not freely enter the higher-pressure region in the compressed lungs.
E)all of the above

Question 36

Inside the same room, buoyant force is greater on

A)a helium-filled party balloon.
B)an elephant.
C)both the same

Question 37

A buoyant force acts on

A)gas-filled balloons.
B)you and your classmates.
C)both of these
D)neither of these

Question 38

Archimedes' principle applies to

A)liquids.
B)gases.
C)fluids.
D)all of the above

Question 39

The flight of a blimp best illustrates

A)Archimedes' principle.
B)Pascal's principle.
C)Bernoulli's principle.
D)Boyle's law.

Question 40

When a gas in a container is squeezed to half its volume with no change in temperature, the gas pressure

A)halves.
B)doubles.
C)quadruples.
D)remains the same.

Question 41

As a balloon high in the atmosphere descends, it undergoes a decrease in

A)volume.
B)density.
C)weight.
D)mass.
E)none of the above

Question 42

The principle of continuity states that for fluid flow to be continuous it must

A)speed up in narrow regions of flow.
B)slow down in wide regions of flow.
C)both of these
D)neither of these

Question 43

As a fluid gains speed, its internal pressure

A)increases.
B)remains unchanged.
C)decreases.

Question 44

Airplane flight best illustrates

A)Archimedes' principle.
B)Pascal's principle.
C)Bernoulli's principle.
D)Boyle's law.

Question 45

A car with closed windows makes a left hand turn. A helium-filled balloon in the car moves to the

A)right.
B)left.
C)front.
D)back.
E)none of the above

Question 46

Assuming no change in temperature, as a freely expanding helium-filled balloon rises in the atmosphere, the buoyant force acting on it

A)increases.
B)decreases.
C)remains nearly the same.

Question 47

According to the principle of continuity, the velocity of a fluid multiplied by the cross section through which it flows at one point will equal the product of

A)velocity and cross section at another point.
B)velocity and pressure at another point.
C)a constraint factor.
D)none of the above

Question 48

A common 5-liter metal can will float in air if it is

A)evacuated of air.
B)filled with a very large amount of helium.
C)thrown high enough.
D)no way, unless the displaced air weighs more than the can and its contents!

Question 49

When water is turned on in a shower, the shower curtain moves towards the water spray. This partly involves

A)capillary action.
B)surface tension.
C)pressure changes in moving fluids.
D)none of the above

Question 50

A large block of wood and a smaller block of iron on weighing scales both register 1 ton. Taking buoyancy of air into account, which has the greater mass?

A)wood
B)iron
C)both have the same mass.
D)need more information

Question 51

As a balloon rises higher and higher into the atmosphere its

A)volume decreases.
B)density increases.
C)weight increases.
D)mass decreases.
E)none of the above

Question 52

If you stand on a weighing scale and suddenly the atmosphere vanishes, taking buoyancy into account, the scale reading

A)increases.
B)decreases.
C)remains the same.
D)quickly reduces to zero.

Question 53

An empty jar is pushed open-side downward into water so that trapped air cannot escape. As it is pushed deeper, the buoyant force on the jar

A)increases.
B)decreases.
C)increases, then decreases.
D)decreases, then increases.
E)remains the same.

Question 54

Release a ball inside a freely falling elevator and it falls directly in front of you instead of "falling to the floor," because you, ball, elevator, and enclosed air are in free fall. If you do the same with a helium-filled balloon, the balloon will

A)also remain in front of you.
B)press against the ceiling.
C)press against the floor.
D)slowly rise.
E)slowly fall.

Question 55

A helium-filled balloon released in the atmosphere will rise until

A)the pressure inside the balloon equals atmospheric pressure.
B)atmospheric pressure on the bottom and top of the balloon are equal.
C)the balloon and surrounding air have equal densities.
D)all of the above
E)none of the above

Question 56

Wind blowing over the top of a hill

A)increases atmospheric pressure there.
B)decreases atmospheric pressure there.
C)does not affect atmospheric pressure there.

Question 57

As a high-altitude balloon rises higher into the atmosphere, it undergoes a decrease in

A)volume.
B)density.
C)weight.
D)mass.
E)none of the above

Question 58

Compared to the buoyant force of the atmosphere on a 1-kilogram iron block, the buoyant force on a nearby 1-kilogram helium-filled balloon is

A)considerably less.
B)considerably more.
C)the same.

Question 59

An object in a vacuum has no

A)buoyant force.
B)mass.
C)weight.
D)temperature.
E)all of the above

Question 60

Compared with the buoyant force of the atmosphere on a 1-liter helium-filled balloon, the buoyant force of the atmosphere on a nearby 1-liter solid iron block is

A)considerably less.
B)considerably more.
C)the same.

Question 61

When you blow air between a pair of closely-spaced Ping-Pong balls suspended by strings, the balls will swing

A)toward each other.
B)away from each other.
C)away from the air stream, but not necessarily toward or away from each other.

Question 62

Glowing plasma is evident in the light from

A)a fluorescent lamp.
B)the aurora borealis (northern lights).
C)some TV screens.
D)all the above
E)none of the above

Question 63

The Bernoulli effect causes passing ships to be drawn together when the ships are close and moving in

A)the same direction.
B)opposite directions.
C)either of these

Question 64

A plasma differs from a gas in that

A)its molecules are farther apart.
B)it is hotter than a gas.
C)it is electrically conducting.
D)its atoms are boosted to higher atomic numbers.
E)all of the above

Question 65

The tarp covering on a trailer or truck puffs upward for fast-moving vehicles, which illustrates

A)Pascal's principle.
B)Archimedes' principle.
C)the principle of continuity.
D)Bernoulli's principle.

Question 66

Most of the matter in our galaxy is in the

A)solid phase.
B)liquid phase.
C)gaseous phase.
D)plasma phase.
E)none of the above

Question 67

The Bernoulli effect causes fast-moving vans on the highway to be drawn together when

A)air speeds up in passing between them.
B)air between them stagnates.
C)they experience lift.
D)all of the above

Question 68

When a common fluorescent lamp is lit, the mercury vapor inside is actually in a

A)gaseous phase.
B)liquid phase.
C)plasma phase.
D)solid phase.
E)none of the above

Question 69

A spinning tossed baseball veers off course in the direction of

A)crowded streamlines.
B)non-crowded streamlines.
C)onward-coming streamlines.

Question 70

Most of the mass of material that makes up a plasma is

A)electrically neutral.
B)always positively charged.
C)always negatively charged.

Question 71

An umbrella tends to move upwards on a windy day principally because

A)trapped air under the umbrella, warms, and rises.
B)buoyancy increases with increasing wind speed.
C)air pressure is reduced over the curved top surface.
D)all of the above

Question 72

Which is an example of matter in a plasma phase?

A)dry ice
B)a torch flame
C)molten lava
D)liquid hydrogen
E)none of the above

Question 73

Most of the matter in the universe is in the

A)solid phase.
B)liquid phase.
C)gaseous phase.
D)plasma phase.
E)none of the above

Question 74

When a gas is heated and becomes a plasma, its electric charge is usually

A)balanced.
B)negative.
C)positive.
D)non-existent.
E)none of these

Question 75

Plasmas are a central part of power generation in

A)MHD generators.
B)turbo generators.
C)both of these
D)neither of these

Question 76

Which of the following bodies is comprised mostly of plasma?

A)Earth
B)Moon
C)Sun
D)all of the above
E)none of the above

Question 77

A spinning tossed baseball veers off course in the direction of

A)reduced air pressure on the ball.
B)increased air pressure on the ball.
C)non-crowded streamlines.

Question 78

The main difference between gases and plasmas has to do with

A)the kinds of elements involved.
B)interatomic spacing.
C)electrical conduction.
D)fluid pressure.
E)the proportion of matter to antimatter in the universe.