For the indicator diagram given below, which of the following is not correct?

A thermodynamic system undergoes cyclic process ABCDA as shown in figure. The work done by the system in the cycle is

1. ρ_oV_o 
 

2. 2ρ_oV_o
 

3. ρ_oV_o/2
 

4. zero

If Q, E and W denote respectively the heat added, change in internal energy and the work done in a closed cyclic process, then

1. W=0                                 

2. Q=W=0

3. E=0                                   

4. Q=0

In a cyclic process, the internal energy of the gas:

A thermodynamic system is taken through the cycle PQRSP process. The net work done by the system is -

(1) 20 J

(2) – 20 J

(3) 400 J

(4) – 374 J