Question

In a heat engine, if 700 j of heat enters the system, and the piston does 400 j of work, what is the final internal energy of the system if the initial energy is 1,200 j?
A 1,100 J
B 300 J
C 1,500 J
D 900 J

Answer 1

Given that

Heat (Q) = 700 J ,

Work (W) = 400 J ,

What is the final  internal energy of the system (u₂) = ?

                                       given  (u₁) = 1200 J

         we know that   ΔU = Q - W  Joules,

                        (U₂ - 1100) = 700 - 400

                                   U₂ = 300 +1100

                                         = 1400 J

The final internal energy is 1400 J