Question 1 |
The transfer function of a real system, H(s), is given as:
H(s)=\frac{As+B}{s^2+Cs+D}
where A, B, C and D are positive constants. This system cannot operate as
H(s)=\frac{As+B}{s^2+Cs+D}
where A, B, C and D are positive constants. This system cannot operate as
low pass filter. | |
high pass filter | |
band pass filter. | |
an integrator. |
Question 1 Explanation:
Put s=0, H(0)=\frac{A \times 0+B}{0+C \times 0+D}=\frac{B}{D}
So, the system pass low frequency component. Put s=\infty , H(\infty )=0
For high pass filter, high frequency component should be non zero. Hence this system cannot be operated as high pass filter.
So, the system pass low frequency component. Put s=\infty , H(\infty )=0
For high pass filter, high frequency component should be non zero. Hence this system cannot be operated as high pass filter.
Question 2 |
For an ideal MOSFET biased in saturation, the magnitude of the small signal
current gain for a common drain amplifier is
0 | |
1 | |
100 | |
infinite |
Question 2 Explanation:
For ideal MOSFET, i_G=0
Therefore, Current gain, A_I=\frac{i_s}{i_G}=\infty
Therefore, Current gain, A_I=\frac{i_s}{i_G}=\infty
Question 3 |
The most commonly used relay, for the protection of an alternator against loss of
excitation, is
offset Mho relay. | |
over current relay. | |
differential relay | |
Buchholz relay. |
Question 4 |
The geometric mean radius of a conductor, having four equal strands with each strand
of radius 'r', as shown in the figure below, is


4r | |
1.414r | |
2r | |
1.723r |
Question 4 Explanation:
Redraw the configuration:

\therefore \; GMR=(r' \times 2r\times 2r\times 2\sqrt{2}r)^{1/4}
Where, r'=0.7788r
Hence, GMR=1.723r

\therefore \; GMR=(r' \times 2r\times 2r\times 2\sqrt{2}r)^{1/4}
Where, r'=0.7788r
Hence, GMR=1.723r
Question 5 |
The valid positive, negative and zero sequence impedances (in p.u.), respectively, for
a 220 kV, fully transposed three-phase transmission line, from the given choices are
1.1, 0.15 and 0.08 | |
0.15, 0.15 and 0.35 | |
0.2, 0.2 and 0.2 | |
0.1, 0.3 and 0.1 |
Question 5 Explanation:
We have,
X_0 \gt X_1=X_2
(for 3-\phi transposed transmission line)
X_0 \gt X_1=X_2
(for 3-\phi transposed transmission line)
There are 5 questions to complete.