# Input impedance of a folded dipole antenna is about

1.  110Ω

2.  220Ω

3.  377Ω

4.  280Ω

4

280Ω

Explanation :
No Explanation available for this question

# If the diameter of parabolic reflector of a microwave antenna is double its gain will increase by

1.   0dB

2.  2 dB

3.   4 dB

4.  6 dB

4

6 dB

Explanation :
No Explanation available for this question

# Top loading is used with a vertical antenna in order to increase its

1.  Beam width

2.   Input capacitance

3.  Effective height

4.  All of these

4

Effective height

Explanation :
No Explanation available for this question

# If the length of an antenna is increased, its directive gain

1.  Increases

2.  Decreases

3.  Becomes infinite

4.  Remain same

4

Increases

Explanation :
No Explanation available for this question

# For a unit step input, a system with forward path transfer function G(s) = 20/s2 and feedback path transfer function H(s) = (s+5), has a steady state output of

1.   0

2.   5

3.  0.2

4.   Zero

4

0.2

Explanation :
No Explanation available for this question

# Consider a system shown in the given figure If the system is disturbed so that C(0) = 1 then C(t) for a unit step input will be

1.  1+t

2.  1-t

3.   1+2t

4.  1-2t

4

1+2t

Explanation :
No Explanation available for this question

# Which one of the following statements is true for gain margin and phase margin of two closed-loop system having loop transfer function G(s) H(s) and exp (-s) G(s) H(s)

1.   Both gain and phase margins of the two systems will be identical

2.   Both gain and phase margins of G(s) H(s) will be more

3.  Gain margins of the two systems are the same but phase margin of G(s) H(s) will be more

4.  Phase margins of the two systems are the same but gain margin of G(s) H(s) will be less

4

Gain margins of the two systems are the same but phase margin of G(s) H(s) will be more

Explanation :
No Explanation available for this question

# An effect of phase-lag compensation on servo system performance is that

1.  For a given relative stability, the velocity constant is increased

2.  For a given relative stability, the velocity constant is decreased

3.  The bandwidth of the system increased

4.  The time response is made faster.

4

For a given relative stability, the velocity constant is increased

Explanation :
No Explanation available for this question

# Compared to resonant antenna, the directive gain of anon-resonant antenna of the same length will be

1.  Smaller

2.   Greater

3.   The same

4

Greater

Explanation :
No Explanation available for this question

# Microwave antenna have

1.  High directivity

2.  High gain

3.  Low input impedance

4.  Wide frequency range

4