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 physics energy production

Green house effect is the:

  1. trapping of radiation in the atmosphere

  2. trapping of water molecule in the atmosphere

  3. trapping of gases in the atmosphere

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

Our atmosphere allows the high frequency radiation (Infrared rays) to pass through it, which comes from sun. This radiation reaches to earth and after some absorption (this radiation is also absorbed and radiated by green house gases), earth reflects back low frequency radiation (Infrared rays) which cannot pass through the atmosphere. This radiation is trapped in our atmosphere and keeps our atmosphere warm, this is called green house effect.

Multiple choice physics heat and energy

Temperature of earth's atmosphere in absence of green house gases in it:

  1. remain constant

  2. increased

  3. decreased

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

The green house gases absorb some of  the radiation (which is reflected by earth, clouds etc.) and the rest is passed into space. Due to that absorbed radiation, earth's atmosphere remains warm. If green house gases would absent, no radiation will stay on earth's atmosphere and temperature of atmosphere will go fall to approx. $-18^{o}C$ which will freeze all the water on earth. 

Multiple choice

Clouds contain water vapor.

  1. true

  2. false
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Clouds are visible accumulations of minute water droplets or ice crystals suspended in the Earth's atmosphere, which are formed from water vapor.

Multiple choice

More evaporation occurs at night time.

  1. true

  2. false
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Evaporation is driven by solar energy. Since there is less solar radiation reaching the surface at night, evaporation rates are generally lower compared to daytime.

Multiple choice

Precipitation occurs because

  1. the droplets evaporate in the air

  2. the droplets are too light for the air to hold

  3. the droplets are too heavy for the air to hold
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Precipitation occurs when water droplets or ice crystals in clouds become too large and heavy for the updrafts in the atmosphere to keep them suspended. Gravity then causes them to fall to the surface.

Multiple choice dew point and humidity heat physics

The most comfortable value for Relative Humidity is

  1. 10%

  2. 20%

  3. 50%

  4. 90%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

50% 

because in this case it won't be too dry or wont be too wet.

Multiple choice dew point and humidity heat physics

At dew point. Relative Humidity is

  1. 10%

  2. 20%

  3. 50%

  4. 100%
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Dew point is when air gets saturated i.e RH =100%

Multiple choice dew point and humidity heat physics

Write the correct alternatives :
The vapour content in the air is measured using  a physical quantity called...............

  1. Absolute humidity

  2. Relative humidity

  3. Dew point

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

Relative humidity :

The ratio of the amount of water vapour actually present in the air to the greatest amount possible at the same temperature.
$\therefore$ option $"B"$ is correct.

Multiple choice dew point and humidity heat physics

When it is raining, the dew point is

  1. $0^\circ C$
  2. $50^\circ C$
  3. $100^\circ C$

  4. room temperature
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
When it is raining, the dew point is room temperature.
The dew point is the temperature at which air can hold the amount of mixture present in atmosphere. If the temperature falls below it, some water vapour must condense.
Multiple choice dew point and humidity heat physics

When the room temperature becomes equal to the dew point, the relative humidity of the room is

  1. $100$%

  2. Zero%
  3. $70$%
  4. $85$%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Relative humidity is the ratio of water vapor pressure and saturation vapor pressure at the present temperature.
When the room temperature becomes equal to the dew point, then the air is saturated. Hence the relative humidity of room is $100$ %.

Multiple choice dew point and humidity heat physics

We feel most comfortable at relative humidity at:

  1. < 50%

  2. 50%

  3. > 50%

  4. 100%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Relative humidity is the ratio of the current absolute humidity to the highest possible absolute humidity which depends on the air temperature. A reading of 100 percent relative humidity means that the air is totally saturated with water vapour and cannot hold any more, creating the possibility of rain. We feel most comfortable at relative humidity 50%.

Multiple choice dew point and humidity heat physics

On a day during the Monsoon season, the relative humidity at a place is 90% and the temperature is $15^\circ$ (C) The saturation vapour pressure of water at this temperature is $0.0169\, \times\, 10^5$ Pa. The partial pressure of water vapour in the air on that day is

  1. $0.9\, \times\, 10^5$ Pa
  2. $0.0169\, \times\, 10^5$ Pa
  3. $0.0152\, \times\, 10^5$ Pa
  4. $1.0\, \times\, 10$^5$ Pa
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Relative humidity=$\dfrac { \text{Partial pressure of }{ H } _{ 2 }0 }{ \text{Vapour pressure of } { H } _{ 2 }0 }\times100\%$
Let the partial pressure of $H _20$ be $x\rho a$
$90=\dfrac { x }{ 0.169\times { 10 }^{ 5 } } \times 100\\ $
$\dfrac { 90 }{ 100 } \times \dfrac { 169 }{ { 10 }^{ 4 } } \times { 10 }^{ 5 }=x$
$x=169\times9$
$x=1521\rho a$
$=0.0152\times10^5\rho a$

Multiple choice dew point and humidity heat physics

When air is saturated, it cannot hold ____________.

  1. more water vapour

  2. more air

  3. more carbon dioxide

  4. more oxygen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When a volume of air at a given temperature holds the maximum amount of water vapour, the air is said to be saturated.

Multiple choice dew point and humidity heat physics

At dew point. RH is _______.

  1. 10%

  2. 30%

  3. 50%

  4. 100%
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The dew point is the temperature at which air is saturated with water vapor, which is the gaseous state of water. The relative humidity is 100 percent when the dew point and the temperature are the same.
Multiple choice dew point and humidity heat physics

The relative humidity on a day when partial pressure of water vapour is $0.012 \times 10^5 Pa$ at $12^oC$ is (Take vapour pressure of water at this temperature as $0.016 \times 10^5$ Pa)

  1. 70%

  2. 40%

  3. 75%

  4. 25%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Given,

Partial pressure of water vapour $={ 0.125\times 10 }^{ 5 }$ Pa
Vapour pressure of water$={ 0.016\times 10 }^{ 5 }$ Pa
Relative humidity at a given temperature (R) 
$=\dfrac { Partial\quad pressure\quad of\quad water\quad vapour }{ vapour\quad pressure\quad of\quad water } \ =\dfrac { { 0.125\times 10 }^{ 5 } }{ { 0.016\times 10 }^{ 5 } } \ =0.75\ =75%$