 # Quiz: Electrical Engineering 27 June 2020

Quiz: Electrical Engineering
Exam: NLC
Topic: Control system

Each question carries 1 mark.
Negative marking: 1/4 mark
Time: 10 Minute

1. Effect of feedback on the plant is to
a) Control system transient response
b) Reduce the sensitivity to plant parameter variations
c) Both (a) and (b)
d) None of these

2. Transfer function of a system is defined as the ratio of output to input in
a) Z-transformer
b) Fourier transform
c) Laplace transform
d) All of these

3. Electrical resistance is analogous to
a) Inertia
b) Dampers
c) Spring
d) Fluid capacity

4. Relation between Fourier integral and Laplace transformer is through
a) Time domain
b) Frequency domain
c) Both (a) and (b)
d) None of these

5. At resonance peak, ratio of output to input is
a) Zero
b) Lowest
c) Highest
d) None of these

6. If gain of the system is zero, then the roots
a) Coincide with the poles
b) Move away from the zeros
c) Move away from the poles
d) None of these

7. Settling time is inversely proportional to product of the damping ratio and
a) Time constant
b) Maximum overshoot
c) Peak time
d) Undamped natural frequency of the roots

8. If gain of the critically damped system is increased, the system will behave as
a) Under damped
b) Over damped
c) Critically damped
d) Oscillatory

9. If gain of the system is increased, then
a) Roots move away from the zeros
b) Roots move towards the origin of the S-plot
c) Roots move away from the poles
d) None of these

10. Physical meaning of zero initial condition is that the
a) System is at rest and stores no energy
b) System is at rest but stores energy
c) Reference input to working system is zero
d) System is working but stores no energy

Solution

Sol 1. (c)
Both (a) and (b)

Sol 2. (c)
Laplace transform

Sol 3. (b)
Inertia

Sol 4. (c)
Both Time domain and frequency.

Sol 5. (c)
At resonance peak, ratio of output to input is highest.

Sol 6. (a)
Coincide with the poles

Sol 7. (b)
Maximum overshoot

Sol 8. (a)
Under damped

Sol 9. (c)
Roots move away from the poles

Sol 10. (a)
System is at rest and stores no energy