Tag: properties of air

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Questions Related to properties of air

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

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

The speed and the direction of wind are based on which of the following? 

  1. Pressure gradient force

  2. Coriolis force

  3. Friction

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

Pressure gradient force,

winds balanced by the Coriolis and Pressure Gradient forces. An air parcel initially at rest will move from high pressure to low pressure because of the pressure gradient force (PGF). ... As the wind gains speed, the deflection increases until the Coriolis force equals the pressure gradient force.
Coriolis force,
The Coriolis effect influences wind by deflecting its path to the right in the Northern Hemisphere. The sequence of weather satellite images shows that the actual wind direction is from the southwest. The satellite images show atmospheric motion over the northern Pacific Ocean for a 36-hour period.
Friction,
 Winds affected by friction. Geostrophic wind blows parallel to the isobars because the Coriolis force and pressure gradient force are in balance. ... As we move higher, surface features affect the wind less until the wind is indeed geostrophic.

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.