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Himanshu posted an Question
April 26, 2020 • 08:55 am 30 points
  • IIT JAM
  • Physics (PH)

Entropy numerical

I am doing this by applying dS= ML/T as the state is changing and my answer comes 0.304 but ACTUAL ANSWER is "0.34" so help!!!!

2 Answer(s) Answer Now
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  • Dushyant bathla

    unit of latent heat is wrong correct unit is cal/gram-K

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    Ruby negi best-answer

    look dear, when state change then temperature also change as temp of ice is zero degree Celsius and of water is 100° Celsius.. in this case ice is at -10° so u have to first change temperature of ice into 0°(273k) use dQ=mcdT then temperature remains constant and state change from ice to water And ur dQ=mL , so now water is at 273k then change temperature from 273k to 283k using dQ=mcdT.. remember when state change then temperature also change so u have to find dS when state change and then when temperature change( this is the usual mistake that everyone done).. hope now u will never make mistake on these type of question, for any doubt please ask.. good luck.

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    Abhishek singh Best Answer

    There is a mistake in the units of Cv and Cs. it should be, Cal/g/K. There are three steps involved as shown in the attached below. step 1 and 3 are taking place due to change in temperature, Hance you have to integrate temperature taking it as variable. but in step 2 , temperature is constant, because is the the process of change of state, and change of state takes place at constant temperature. go through the solution, you will yourself find the mistake you made and learn from the mistake. Best regards.

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    Shanu arora

    Here is the detailed solution , you have just done a calculation mistake and that's fine it happens with everybody once in a while. feel freefor more doubts

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    Shanu arora

    here is the detailed solution , you just did a calculation mistake and that's okay once in while happens with everyone , feel free for more doubts

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