Tag: in search of the source of wind

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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 the concept of bernoulli's principle air exerts pressure

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

  1. Homosphere

  2. Heterosphere

  3. Atmosphere

  4. Troposphere
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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 heat zones of earth arises due to ________ difference.

  1. temprature

  2. pressure

  3. humidity

  4. All of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The heat zone of earth arises due to the temperature difference. The classification of heat zones of the earth was first done by Greek Scholar Aristotle. The different heat zones of earth are: - Torrid Zone, Frigid Zone and Temperate zone. All these zones have different temperature range. Torrid Zone is the hottest zone among the zones of the earth.

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

What is the level of mercury at normal atmospheric pressure?

  1. 64 cm

  2. 70 cm

  3. 76 cm

  4. 80 cm
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$76cm$

Atmospheric pressure is expressed in several different systems of units: millimetres (or inches) of mercury, pounds per square inch (psi), dynes per square centimetre, millibars (mb), standard atmospheres, or kilopascals. Standard sea-level pressure, by definition, equals 760 mm (29.92 inches) of mercury, 14.70 pounds per square inch, 1,013.25 × 103 dynes per square centimetre, 1,013.25 millibars, one standard atmosphere, or 101.325 kilopascals. Variations about these values are quite small; for example, the highest and lowest sea-level pressures ever recorded are 32.01 inches (in the middle of Siberia) and 25.90 inches (in a typhoon in the South Pacific). The small variations in pressure that do exist largely determine the wind and storm patterns of Earth.

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