A wet cloth has been hung out to dry....

[Akash47]

Homework Statement

Wet clothing at 0°C is hung out to dry when the air temperature is 0°C and there is a dry wind blowing. After some time, it is found that some of the water has evaporated and the remainder has frozen. Estimate the fraction of the water originally present in the clothing which remains as ice. (At 0°C, specific latent heat of fusion of ice = 336 kJkg^-1, specific latent heat of vaporization of water = 2500 kJkg^-1, specific heat of water = 4200 Jkg^-1K^-1)

Homework Equations

Q=msΔθ where Q=amount of heat,m=mass,s=specific heat ,Δθ=change of temperature.

The Attempt at a Solution

The problem can be solved by using the given formula.But I am facing problem that it is impossible to measure the mass of air and as a result, I also failed to compute the heat supplied by the dry air to the water.So how can I get rid of here?

 

[ehild]

Homework Statement

Wet clothing at 0°C is hung out to dry when the air temperature is 0°C and there is a dry wind blowing. After some time, it is found that some of the water has evaporated and the remainder has frozen. Estimate the fraction of the water originally present in the clothing which remains as ice. (At 0°C, specific latent heat of fusion of ice = 336 kJkg^-1, specific latent heat of vaporization of water = 2500 kJkg^-1, specific heat of water = 4200 Jkg^-1K^-1)

Homework Equations

Q=msΔθ where Q=amount of heat,m=mass,s=specific heat ,Δθ=change of temperature.

The Attempt at a Solution

The problem can be solved by using the given formula.But I am facing problem that it is impossible to measure the mass of air and as a result, I also failed to compute the heat supplied by the dry air to the water.So how can I get rid of here?

Does air of 0°C supply heat to water also at 0°C? Where does the heat come that evaporates the water?

 

[Akash47]

Does air of 0°C supply heat to water also at 0°C? Where does the heat come that evaporates the water?

I am not sure whether the air of 0°C supply heat.But of course the heat comes from the dry air.But that doesn't solve my problem which I mentioned in my attempt of the solution.

 

[ehild]

I am not sure whether the air of 0°C supply heat.But of course the heat comes from the dry air.But that doesn't solve my problem which I mentioned in my attempt of the solution.

The dry wind removes the water vapor, and keeps the cloth at 0°C. But where does the heat come that evaporates the water? Think: what happens if water freezes?