Download EE2010 - Second Mid Term Exam Model Answer

Model Answer of the Following Questions:
Question No. (1)
(5 marks)
(1-A)
(2.5 marks)
The variable resistor in the circuit shown in Figure (1-A) is adjusted for maximum power
transfer to Ro.
(a) Find the value of Ro.
(b) Find the maximum power that can be delivered to Ro.
(c) Find the percentage of the total power developed in the circuit that is delivered to
Ro.
Figure (1-A) Question (1)
Solution:
1-16
2-16
3-16
(1-B)
Use the principle of superposition to find the following:
(a) The voltage v in the circuit shown in Figure (1-B).
(b) The power dissipated in the 20 resistor
Figure (1-B) Question (1)
Solution:
4-16
(2.5 marks)
5-16
Question No. (2)
(9 marks)
(2-A)
(2 marks)
For the circuit shown in Figure (2-A), use the concept of voltage division to find the steady
state expression of vo.
vg= 75 cos 5000t V
Figure (2-A) Question (2)
Solution:
6-16
(2-B)
(3 marks)
Find the Thevenin equivalent circuit with respect to the terminals a, b for the circuit shown
in Figure (2-B).
Figure (2-C) Question (2)
Solution:
7-16
8-16
(2-C)
(3 marks)
Use the node-voltage method to find the branch currents ia and ib in the circuit shown in
Figure (2-C).
va= 100 sin 10000t V
vb= 500 cos 10000t V
Figure (2-C) Question (2)
Solution:
9-16
10-16
(2-D)
(3 marks)
For the circuit shown in Figure (2-D), use the mesh-current method to find the steady state
expression of the current io.
va= 8 cos 40000t V
vb= 90 sin (40000t + 180) V
Figure (2-D) Question (2)
Solution:
11-16
Question No. (3)
(6 marks)
(3-A)
(3 marks)
For the circuit shown in Figure (3-A),
(a) Calculate the total average and reactive power delivered to each impedance in the
circuit shown in Figure (3-A).
(b) Calculate the average and reactive power associated with each source in the circuit.
(c) Verify that the average power delivered equals the average power absorbed, and
that the magnetizing reactive power delivered equals the magnetizing reactive power
absorbed.
Figure (3-A) Question (3)
Solution:
12-16
13-16
14-16
15-16
(3-B)
(3 marks)
For the circuit shown in Figure (3-A), find the following:
(a) Find the average power dissipated in the line in Figure (3).
(b) Find the capacitive reactance that when connected in parallel with the load will
make the load look purely resistive.
(c) What is the equivalent impedance of the load in (b)?
(d) Find the average power dissipated in the line when the capacitive reactance is
connected across the load.
Figure (3-B) Question (3)
Solution:
16-16