Braking of DC Motor MCQ [Free PDF] – Objective Question Answer for Braking of DC Motor Quiz

11. Calculate the quality factor for the pure capacitor.

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

Answer: A

The quality factor is defined as the ratio of the reactive power to the active power consumed. The pure capacitor always absorbs reactive power. The value of active power consumed is 0.

Quality factor=Q/0=inf.   

 

12. Calculate the equivalent inductance when n inductors are connected in a series of values L.

A. n2L H
B. nL H
C. .5L H
D. 2 H

Answer: B

When two inductors are connected in series their equivalent inductance is equal to the sum of the individual inductances.

Leq=L+L+…..+n times L=nL H.   

 

13. Calculate the equivalent resistance when two resistances are connected in a series of values 12 Ω, and 10 Ω.

A. 32 Ω
B. 22 Ω
C. 47 Ω
D. 17 Ω

Answer: B

When two resistances are connected in series their equivalent resistance is equal to the sum of the individual resistances.

Req=R1+R2=22 Ω.   

 

14. Reactive power is positive in the case of the inductor.

A. True
B. False

Answer: A

The reactive power is defined as the product of the voltage, current, and sine of the difference between the phase angle of voltage and current. In the case of an inductor, the voltage leads to the current. The value of sine is positive and reactive power is positive.

 

15. Reactive power is positive in the case of the capacitor.

A. True
B. False

Answer: B

The reactive power is defined as the product of the voltage, current, and sine of the difference between the phase angle of voltage and current. In the case of a capacitor, the voltage lags the current. The value of sine is negative and reactive power is negative.   

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16. The sine function is an odd function.

A. True
B. False

Answer: A

The odd functions are those functions that are symmetric about the origin. The sine function is an odd function whose time period is 2π.   

 

17. The cosine function is an even function.

A. True
B. False

Answer: A

The even functions are those functions that are a mirror image of the y-axis. The cosine function is an even function whose time period is 2π.   

 

18. Full form of NENO.

A. Neither even nor odd
B. Neither energy nor odd
C. Neither even nor original
D. Neither even nor orthogonal

Answer: A

NENO stands for Neither even nor odd. The functions which are not the mirror image of the y-axis and not symmetric about the origin are NENO functions.   

 

19. The characteristics shown by an element in the V-I curve are V=Is(1-e-V/K). The nature of the element is _______

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

Answer: D

The nature of the element is non-linear, unilateral, and passive. The shape of the characteristic is exponential rising. It should be symmetrical in the first and third quadrants for bilateral nature. Its slope is positive in the first quadrant which determines its passive nature.   

 

20. Calculate the resonant frequency if the values of the capacitor and inductor are 2 F and 2 H.

A. .5 rad/sec
B. .6 rad/sec
C. .8 rad/sec
D. .9 rad/sec

Answer: A

During resonance condition XL=Xc. The value of the resonant frequency is

1÷√LC=1÷√4=.5 rad/sec.

The voltage across the capacitor and inductor becomes equal.   

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