Physics · Geography

Atmospheric Physics and Humidity

935 Questions

Study the principles of atmospheric physics and humidity through these practice questions. Key subjects include the rate of evaporation, temperature inversions, and relative humidity measurements. These concepts are vital for geography and physics exams.

Evaporation and condensationRelative humidity conceptsAtmospheric pressure effectsTemperature inversion

Atmospheric Physics and Humidity Questions

Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts

 Consider the following statements and identify the right ones.
i) Lower layers of atmosphere have low pressure.
ii) Higher layers of the atmosphere have high pressure.

  1. i only

  2. ii only

  3. both

  4. none of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Although air is well mixed throughout the atmosphere, the atmosphere itself is not physically uniform but has significant variations in temperature and pressure with altitude, which define a number of atmospheric layers i.e. when lower layers have atmospheric pressure and higher ones have low atmospheric pressures due to the altitude.

Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts

Consider the following statements and identify the right ones :-
i) Air pressure decreases when air descends.
ii) Air pressure at sea level is lower than at the mountain top.

  1. i only

  2. ii only

  3. Both

  4. None
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Air pressure increases when air descends. Lower pressure at higher altitudes cause the temperature to be colder on top of a mountain than at sea level. As air rises, the pressure decreases. It is this lower pressure at higher altitudes that causes the temperature to be colder on top of a mountain than at sea level.

Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts

Which of the following affects atmospheric pressure?

  1. Altitude

  2. Temperature

  3. Rotation of Earth

  4. All the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The factors which affects in the distribution oof atmospheric pressure are, altitude, temperature and rotation of the earth. Atmospheric pressure decreases with increaseing altitude. Regional variation of pressure are produced by temperature. Movement of wind are also responsible for pressure channge, prevailing wind systems are caused by rotation of the earth.

Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts

The weight of water vapour per unit weight of air is called?

  1. Specific Humidity

  2. Relative humidity

  3. Absolute Humidity

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The weight of water vapor per unit weight of air is called Specific humidity. It is usually expressed as grams of vapor per kilogram of air. The rate of evaporation of water from any surface is directly proportional to the specific humidity, the difference between the surface and the adjoining air. It is an extremely useful quantity in meteorology. Specific humidity does not change with temperature and pressure.

Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts

Consider the following statements and identify the right ones.
i) The low temperature at poles causes air to expand.
ii) High temperatures along equator cause air to contract.

  1. (i) only

  2. (ii) only

  3. Both of these

  4. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Low temperature causes air to contract and higher temperature causes air to expand.

Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts

 Consider the following statements and identify the right ones.
i) The temperature of the air rises when its pressure falls.
ii) The pressure of the air falls when the temperature rises.

  1. i only

  2. ii only

  3. Both of these

  4. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

As air warms up, the molecules in the air become more active and they use up more individual space. This leads to a rise in the air pressure. Similarly, when the air cools down the molecules remain compact, leading to a decrease in air pressure.

Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts the concept of bernoulli's principle air exerts pressure

In the Earth's atmosphere, the atmospheric pressure  ________.

  1. remains constant with height

  2. increases with height

  3. decreases with height

  4. first increase and then decrease with height
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

As we go up the pressure decreases with altitude.

This is because at higher altitudes number of air molecules present are low when compared to those that are present in the lower atmosphere.

Moreover gravitational pull which is responsible for atmospheric pressure is low on the molecules that are away from its surface than those that are closer to it.

Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts

Which of the following factor affect atmospheric pressure?

  1. Altitude

  2. Temperature and amount of moisture

  3. Rotation of the earth

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Temperature: When the temperature of a place increases, the atmospheric pressure decreases. This happens because an increase in the temperature results in the heating of the air. Warm air expands. The molecules of the warm air become less dense and hence exert less pressure. On the contrary, decrease in temperature makes the air cool and dense. This creates a high pressure area in a region.

Altitude: Atmospheric pressure decreases with an increase in the altitude. Air is compressible. As the gravity of the Earth pulls the molecules and gases towards the ground, the lowest layer of the air becomes densest. This dense layer of air exerts the greatest pressure.

Rotation of the Earth: The rotation of the Earth causes the air at the Poles to be pushed away towards the Equator. In theory, air should have been accumulated at Equator creating a high pressure belt. However, this does not happen. On the contrary, the air gets heated at the Equator, and rises up creating a low pressure.
Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts the concept of bernoulli's principle air exerts pressure

A column of air 1 sq. cm. in cross-sectional area extending from sea-level to the top of the atmosphere weights approximately ______.

  1. 933 g wt

  2. 1033 g wt

  3. 1136 g wt

  4. 1360 g wt
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
1033 g wt
Air pressure at sea level is about 101 000 Pa. A Pa (pascal), by definition, is a newton per square meter. 
So the weight, force of that column which is 1 square meter in cross-section area is 101000 newtons. 
There are 10000 cm² per m², so we get 
the weight, force of that column 1 square cm in cross-section area is 10.1 newtons ⬅ 
Using F = ma or Weight = mass x acceleration of gravity, 
10.1 newtons corresponds to a mass of 10.1 N / 9.8 = 1.03 kg ⬅ 

that is approximate and does not account for the weight decreasing as you go up in altitude. But most of the air is at low altitudes, so it's close. 
Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts

When altitude increases pressure __________.

  1. increases

  2. decreases

  3. remains constant

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Air pressure always decrease with the increase of altitude but not always uniform. The decrease is caused by the compressional  effect of the air from above and its density. It is estimated that the pressure decreases at an average one centimeter for every 110 meters.

Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts

The weight of humid air is _______ to than dry air.

  1. more

  2. less

  3. equal

  4. equivalent
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The weight of humid air is less to than dry air.


Our air is primarily composed of nitrogen and oxygen, but it always has some water molecules.

The weight of an individual atom is represented by its atomic weight. The (rounded) atomic weight of hydrogen (H) is 1, oxygen (O) is 16, nitrogen (N) is 14, and carbon (C) is 12.

The weight of a molecule is determined by summing the atomic weights of its atoms. A water molecule (H2O) has a molecular weight of 18 (1 + 1 + 16). Free nitrogen (N2) has a molecular weight of 28, and an oxygen molecule (O2) has an atomic weight of 32. Therefore, a water molecule is lighter than either a nitrogen or an oxygen molecule.

Any fixed volume of a gas at constant pressure and temperature has the same number of molecules. It does not matter what the gas is — the same number of molecules will exist in that volume.

To make a given volume of air moister, we need to add water vapor molecules to the volume. To add water molecules to the volume, we must remove other molecules to conserve the total number of molecules in the volume.

Dry air consists mostly of nitrogen and oxygen molecules, which weigh more than water molecules. This means that when a given volume of air is made more moist by adding water molecules, heavier molecules are replaced with lighter molecules. Therefore, moist air is lighter than dry air if both are at the same temperature and pressure

Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts the concept of bernoulli's principle air exerts pressure

The atmospheric pressure decreases at the rate of ______________.

  1. 1 millibar/altitude of 10 meters

  2. 1 millibar/altitude of 15 meters

  3. 1 millibar/altitude of 18 meters

  4. 1 millibar/altitude of 20 meters
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Near Earth's surface the pressure decreases with height at a rate of about 1 millibars for every 10 metres. However, over cold air the decrease in pressure can be much steeper because its density is greater than warmer air.

Multiple choice geography in search of the source of wind variations in atmospheric pressure properties of air pressure belts the concept of bernoulli's principle air exerts pressure

When the temperature increases atmospheric pressure _________.

  1. increases

  2. decreases

  3. remains same

  4. became zero
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

There exists a negative relation between pressure and temperature. When temperature increases pressure will fall and vice versa. That is why, pressure increases from equatorial region towards the polar region.