# Countercurrent Braking MCQ

1. The value of unit step function at t=5 sec is ________

A. 0
B. 1
C. -1
D. 2

The unit step function is discontinuous at t=0.

The value of the unit step function is 1

for t>0 and zero for t<0.

It is a right-handed and bounded signal.

2. The value of impulse at t=0 is __________

A. 0
B. 2
C. 1
D. infinite

The impulse function is neither an energy signal nor a power signal. It is a pulse of infinite amplitude and zero width. The value of impulse is 0 for time not equal to zero.

3. What is the Full form of IFOC?

A. Indirect field-oriented control
B. Inverter field-oriented control
C. Isolated field-oriented control
D. Insight field-oriented control

IFOC stands for indirect field-oriented control. DTC and IFOC are the techniques used for controlling the speed and torque of a 3-phase induction motor.

4. The characteristic shown by an element in the I-V curve is a straight line passing through the origin with a positive slope. The nature of the element is _______

A. Non-linear, Bilateral
B. Linear, Unilateral
C. Linear, Bilateral
D. Non-linear, Unilateral

The nature of the element is linear and bilateral. It follows the principle of homogeneity and the law of additivity. It should be symmetrical in the first and third quadrant for bilateral nature.

5. Calculate the total energy stored in the inductor if the current value is 4 A and inductance values are 1 H and 2 H.

A. 72 J
B. 22 J
C. 82 J
D. 24 J

The energy stored in the inductor is

.5×Leq×I2.

The value of Leq=1+2=3 H.

The total amount of energy stored in the inductor in the steady-state condition.

E=.5×eq×I2

=.5×3×4×4=24 J.

6. Mesh analysis is only applied to the planar circuits.

A. True
B. False

The mesh analysis is one of the network tools to find the responses in the circuits. It is only applicable to planar circuits. Planar circuits are 2-D circuits as mesh analysis involves mesh circulating currents.

7. All loops are meshes.

A. True
B. False

Loop is defined as a closed path that can contain small closed paths. Mesh does not contain any closed path. All meshes are loops but vice-versa is not true.

8. The nodal method is better than mesh analysis for solving circuit problems.

A. True
B. False

The nodal method is one of the best methods to solve any circuit problem. It is based on the KCL equation. It is applicable for planar and non-planar circuits. Mesh analysis cannot be applicable for non-planar circuits.

9. The minimum value of the admittance in the case of the parallel RLC network is ___________

A. R
B. 1÷R
C. Xl-Xc
D. Xc

The minimum value of the admittance in the case of the parallel RLC network is R. During resonance condition

Xl=Xc

so

Y = 1÷Z = (R2+(Xl-Xc)2).5 = 1÷R.

10. Calculate the value of the inductive reactance during resonance if the value of capacitive reactance is 2 ohm.

A. 8 Ω
B. 2 Ω
C. 3 Ω
D. 1 Ω