Thevenin and Norton theorems

Q. The Thevenin's equivalent of the network shown below is,

1. $57.34\angle -55{}^{\circ }Vand(4.7-j6.7)\Omega$
2. $57.34\angle -61{}^{\circ }Vand(4.7-j2.4)\Omega$
3. $55.34\angle -57.3{}^{\circ }Vand(6.7-j4.7)\Omega$
4. $55\angle -24{}^{\circ }Vand(4.2-j6.7)\Omega$

Q. In the figure, $Z_1=10\angle -{60}^{\circ }$, $Z_2=10\angle {60}^{\circ }$, $Z_3=50\angle {53.13}^{\circ }$. Thevenin's impedance seen from X-Y is

1. $56.66\angle {45}^{\circ }$
2. $60\angle {30}^{\circ }$
3. $70\angle {30}^{\circ }$
4. $34.4\angle {65}^{\circ }$

Q.

In the circuit shown in the figure, the angular frequancy $\omega$ (in rad/s), at which the Norton equivalent impendance as seen from terminals b-b' is purely resistive, is

1. 2

Q. The Thevenin's equivalent voltage V${}_{TH}$ appearing between the terminals A and B of the network shown in the figure is given by

1. j16(3 - j4)
2. j16(3 + j4)
3. 16(3 + j4)
4. 16(3 - j4)