Find the external work done by the system in kcal, when 20 kcal of heat is supplied to the system and the increase in its internal energy is 8400 J. (J = 4200 J/kcal).

Find the external work done by the system in kcal, when 20 kcal of hea

1.	Find the external work done by the system in kcal, when 20 kcal of heat is supplied to the system and the increase in its internal energy is 8400 J. (J = 4200 J/kcal).
Answer» Solution :Heat energy supplied `Q = 20 k cal = 20 xx 10^3 `cal Increase in internal energy , `dU = 8400J =(8400 )/(4200) = 2K cal` From 1st Law of thermodynamics dQ = dU+ DW . `therefore `WORK done dW=dQ- dU (SINCE all are in Kilo calories) Work done in Kilocalories = dQ-dU = 18 kcal.