# Express the change in internal energy of a system when (i) No heat is absorbed by the system from the surroundings, but work (w) is done on the system. Whattype of wall does the system have?(ii) No work is done on the system, but q amount of heat is taken out from the system and given to the surroundings. What type of wall does the system have? (iii) w amount of work is done by thesystem and q amount of heat is Supplied to the system. What type of systemwould it be?

2
by Anurup12
what do u mean by wall?
2) thermally conducting wall U=-q
3) closed system U=q-w
why did u write question, if u knew answer?

2014-10-03T12:14:38+05:30

### This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
First law of thermodynamics: ΔU = Q - W
where ΔU = change in Internal energy
Q = Heat added to the system
W = work done by the system

i)Q= 0 ⇒ΔU = 0 - (-W)
⇒ ΔU = W, Wall is adiabatic.
ii)W= 0 ⇒ ΔU = (-Q) -0
ΔU = -Q; Wall is non-adiabatic or thermally conducting
iii)ΔU = Q - W

2014-10-04T18:44:44+05:30
1) we know that u=q+w here q=0 therefore u=w
2) thermal conducting wall
3)adiabatic wall it will be a closed system