Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning - Discussion


The humidity ratio or specific humidity is the mass of water vapour present in

[A]. 1 m3 of wet air
[B]. 1 m3 of dry air
[C]. 1 kg of wet air
[D]. 1 kg of dry air

Answer: Option D


No answer description available for this question.

Rajesh said: (Feb 19, 2013)  
Specific humidity is the proportion of the mass of water vapor per unit mass of the moist air sample (dry air plus the water vapor) it is closely related to humidity ratio and always lower in value.

Dayanand said: (Feb 21, 2015)  
C right because water vapour weight in kg/wet air (dry air+water vapour) in kg.

Ali Hassan said: (Apr 15, 2015)  
D right because the Specific humidity is approximately equal to the "mixing ratio", which is defined as the ratio of the mass of water vapor in an air parcel to the mass of dry air for the same parcel.

Krrish said: (Dec 23, 2015)  
It is not clear can any of you please elaborate it.

Sagar said: (Jan 13, 2016)  
My question is ' How water vapors can be present in dry air' as written in the question?

Amrit said: (May 13, 2016)  
I think humidity ratio is the ratio in the mixture of water vapour and dry air.

Humidity ratio is evaluated from moist air. Eg. If 3kg of dry air is mixed with 2 kg of water vapour then humidity ratio will be 2/3.

Puneet Sharma said: (Jan 17, 2017)  
How can we measure air in terms of 'kg' and how water vapour can be present in 'dry air'?

Puneet said: (Jan 17, 2017)  
Specific humidity, the mass of water vapour in a unit mass of moist air, usually expressed as grams of vapour per kilogram of air.

Thalif Hussain said: (Jan 31, 2017)  
Please explain clearly.

M Masoom Razzaqi said: (Feb 12, 2017)  
Dry air means there is no water suspended particals in air but dry water vapor are preent. Therefore these dry vapors %age is called specific humidity ratio.

Chouhan said: (Mar 9, 2017)  
C is correct because dry air is mixing of water vapour and dry air.

A K said: (May 18, 2017)  
Yes, you are right @Masoom.

Getnet said: (Sep 24, 2018)  
I'm not understanding this question. Please, anyone, help me to get it.

Vishal Kadam said: (Oct 9, 2018)  

No anyone direct measure specific humidity ratio. The scientist already has taken effort by doing a number of experiments and create psychometric charts, there we can directly calculate the humidity ratio if we know the DBT & WBT.

Humidity ratio = mass of water vapour per unit dry air in the moist air. It is the concept.

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