Question

A system absorbs 10 kJ of heat and does work equivalent to 3 kJ. What is the change in internal energy of the system?​

Answer 1

Answer:

Solution:- (A) increases by 6kJ

As given that work is done by the system and heat is absorbed by the system.

Therefore,

q = 10kJ

w = −4kJ

Now from the first law of thermodynamics,

ΔU = q+w

⇒ΔU = 10+(−4) = 6kJ

⇒Uf −Ui =6⇒Uf =(Ui +6)

Hence the internal energy is increased by 6kJ.