A thermodynamic system undergoes a cyclic process \(ABCDA\) as shown in Fig. The work done by the system in the cycle is: 
             
1. \( P_0 V_0 \)
2. \( 2 P_0 V_0 \)
3. \( \frac{P_0 V_0}{2} \)
4. zero

A thermodynamic system is taken through the cycle \(\mathrm{ABCD}\) as shown in the figure. Heat rejected by the gas during the cycle is: 
     

1. \(2 {PV}\)
2. \(4{PV}\)
3. \(\frac{1}{2}{PV}\)
4. \(PV\)

If \(Q\), \(E\), and \(W\) denote respectively the heat added, the change in internal energy, and the work done in a closed cycle process, then:
1. \(W=0\)
2. \(Q=W=0\)
3. \(E=0\)
4. \(Q=0\)