Tag: properties of air

Questions Related to properties of air

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

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

  1. Specific Humidity

  2. Relative humidity

  3. Absolute Humidity

  4. None of the above

Show answer
Correct Option: A
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.

_________ is  created when there is difference in air pressure.

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

  1. Light

  2. Sound

  3. Wind

  4. Rain

Show answer
Correct Option: C
Explanation:

Wind
Air moves from the high-pressure areas to low-pressure areas, creating the wind.
Now with the difference in speeds of traveling wind, it may be called as the storm, hurricane, etc.

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.

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

  1. (i) only

  2. (ii) only

  3. Both of these

  4. None of these

Show answer
Correct Option: D
Explanation:

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

 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.

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

  1. i only

  2. ii only

  3. Both of these

  4. None of these

Show answer
Correct Option: D
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.

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

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

  1. remains constant with height

  2. increases with height

  3. decreases with height

  4. first increase and then decrease with height

Show answer
Correct Option: C
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.

Which of the following is the unit of Atmospheric pressure?

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

  1. Watt

  2. Calories

  3. Bars

  4. Newton

Show answer
Correct Option: C
Explanation:
  • Bars are the unit of pressure hence C is the correct option.
  • Calorie is the unit of energy
  • Newton is the unit of force.
  • Watt is the unit of power.

Which of the following factor affect atmospheric pressure?

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

  1. Altitude

  2. Temperature and amount of moisture

  3. Rotation of the earth

  4. All of the above

Show answer
Correct Option: D
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.

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

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

  1. 933 g wt

  2. 1033 g wt

  3. 1136 g wt

  4. 1360 g wt

Show answer
Correct Option: B
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. 

The pressure and wind systems are actually the impact of Lithosphere and Hydrosphere on ______.

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

  1. Homosphere

  2. Heterosphere

  3. Atmosphere

  4. Troposphere

Show answer
Correct Option: C
Explanation:

Atmosphere,

These spheres are closely connected. For example, many birds (biosphere) fly through the air (atmosphere), while water (hydrosphere) often flows through the soil (lithosphere). Interactions also occur among the spheres; for example, a change in the atmosphere can cause a change in the hydrosphere and vice versa.

When altitude increases pressure __________.

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

  1. increases

  2. decreases

  3. remains constant

  4. none of the above

Show answer
Correct Option: B
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.