Tag: heat

Questions Related to heat

When air is saturated, it cannot hold ____________.

dew point and humidity heat physics

  1. more water vapour

  2. more air

  3. more carbon dioxide

  4. more oxygen

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Correct Option: A
Explanation:

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

At dew point. RH is _______.

dew point and humidity heat physics

  1. 10%

  2. 30%

  3. 50%

  4. 100%

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Correct Option: D
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.

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)

dew point and humidity heat physics

  1. 70%

  2. 40%

  3. 75%

  4. 25%

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Correct Option: C
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) 
$=\dfrac { Partial\quad pressure\quad of\quad water\quad vapour }{ vapour\quad pressure\quad of\quad water } \ =\dfrac { { 0.125\times 10 }^{ 5 } }{ { 0.016\times 10 }^{ 5 } } \ =0.75\ =75%$

Formation of dew is an example for ......

dew point and humidity heat physics

  1. Boiling

  2. Melting

  3. Condensation

  4. Evaporation

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Correct Option: C
Explanation:

It is a example of condensation.Condensation is the process in which gas changes into a liquid when it touches a cooler surface.


Dew drops are formed due to condensation of water vapors. Air around us contains water vapors which we call moisture or humidity. Hot air contains more moisture as compared to cold air. During the night when the hot air comes into contact with some cold surface, water vapor present in it condenses on the cold surface in the form of droplets. These tiny drops of water are called dew drops

When it is raining, the dew point is:

dew point and humidity heat physics

  1. 0$^o$C

  2. 60$^o$C

  3. 100$^o$C

  4. room temperature

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Correct Option: D
Explanation:
The dew point is the temperature at which the air can exactly hold the amount of moisture present. When raining, at any given temperature, the atmosphere can hold so much water vapour. So the dew point is equal to the room temperature.

The temperature of a normal human being is

physics heat application of various thermometric scales different types of thermometers measuring temperature

  1. $31^{o} C$

  2. $37^{o} C$

  3. $20^{o} C$

  4. $50^{o} C$

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Correct Option: B
Explanation:

$98.4^{o} F$ is temperature of normal human being. Which is also equal to $37^{o} C$.

Name the device which is used to measure temperature.

physics heat application of various thermometric scales different types of thermometers measuring temperature

  1. Caloriemeter

  2. Thermometer

  3. Vermier calliper

  4. None

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Correct Option: B
Explanation:

Thermometer is used to measure temperature. The degree of hotness or coldness of a body is temperature.