McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Electrical Engineering .
| 101. |
The constant M-circle represented by the equation x^2+2.25x+y^2=-1.25 has the value of M equal to: |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| Explanation: comparing with the m circle equation we have the value of m =3. | |
| 102. |
What is the value of M for the constant M circle represented by the equation 8x2+18x+8y2+9=0? |
| A. | 0.5 |
| B. | 2 |
| C. | 3 |
| D. | 8 |
| Answer» C. 3 | |
| Explanation: comparing with the m circle equation we have the value of m =3. | |
| 103. |
The constant N loci represented by the equation x^2+x+y^2=0 is for the value of phase angle equal to: |
| A. | -45° |
| B. | 0° |
| C. | 45° |
| D. | 90° |
| Answer» D. 90° | |
| Explanation: centre = (-0.5, 0) centre of n circle is (-1/2, 1/2n) | |
| 104. |
4 DESIGN OF COMPENSATORS USING BODE PLOT |
| A. | -1 and origin |
| B. | origin and +1 |
| C. | -0.5 and 0.5 |
| D. | -1 and +1 |
| Answer» A. -1 and origin | |
| Explanation: centre of n circle is (-1/2, 1/2n) | |
| 105. |
Which one of the following statements is correct? Nichol’s chart is useful for the detailed study analysis of: |
| A. | closed loop frequency response |
| B. | open loop frequency response |
| C. | close loop and open loop frequency responses |
| D. | none of the above |
| Answer» A. closed loop frequency response | |
| Explanation: nichol’s chart is useful for the detailed study analysis of closed loop frequency response. | |
| 106. |
Frequency range of bode magnitude and phases are decided by : |
| A. | the lowest and higher important frequencies of dominant factors of the oltf |
| B. | the lowest and highest important frequencies of all the factors of the open loop transfer function |
| C. | resonant frequencies of the second factors |
| D. | none of the above |
| Answer» D. none of the above | |
| Explanation: t. f. = kp (1+tds) | |
| 107. |
OLTF contains one zero in right half of s- plane then |
| A. | open loop system is unstable |
| B. | close loop system is unstable |
| C. | close loop system is unstable for higher gain |
| D. | close loop system is stable |
| Answer» C. close loop system is unstable for higher gain | |
| Explanation: oltf contains one zero in right half of s-plane then close loop system is unstable for higher gain. | |
| 108. |
The critical value of gain for a system is 40 and gain margin is 6dB. The system is operating at a gain of: |
| A. | 20 |
| B. | 40 |
| C. | 80 |
| D. | 120 |
| Answer» A. 20 | |
| Explanation: gm (db) = 20loggm gm =2 | |
| 109. |
Nichol’s chart is useful for the detailed study and analysis of: |
| A. | closed loop frequency response |
| B. | open loop frequency response |
| C. | close loop and open loop frequency responses |
| D. | open loop and close loop frequency responses |
| Answer» A. closed loop frequency response | |
| Explanation: nichol’s chart is useful for the detailed study and analysis of closed loop frequency response. | |
| 110. |
The roots of the characteristic equation of the second order system in which real and imaginary part represents the : |
| A. | damped frequency and damping |
| B. | damping and damped frequency |
| C. | natural frequency and damping ratio |
| D. | damping ratio and natural frequency |
| Answer» B. damping and damped frequency | |
| Explanation: real part represents the damping and imaginary part damped frequency. | |
| 111. |
An all-pass network imparts only |
| A. | negative phase to the input |
| B. | positive phase to the input |
| C. | 90 degree phase shift to the input |
| D. | 180 degree phase shift to the input |
| Answer» D. 180 degree phase shift to the input | |
| Explanation: an all-pass network is the network that is the combination of the minimum and non-minimum phase systems and have the magnitude 1 for all frequencies and imparts only 180 degree phase shift. | |
| 112. |
Which of the following is an effect of lag compensation? |
| A. | decrease bandwidth |
| B. | improves transient response |
| C. | increases the effect of noise |
| D. | increases stability margin |
| Answer» A. decrease bandwidth | |
| Explanation: lag compensation is the integral compensation that introduces the lag in the response by slowing the response and reducing the steady state error value by decreasing bandwidth. | |
| 113. |
PD controller: |
| A. | decreases steady state error and improves stability |
| B. | rise time decreases |
| C. | transient response becomes poorer |
| D. | increases steady state error |
| Answer» B. rise time decreases | |
| Explanation: in proportional and derivative | |
| 114. |
PID controller: |
| A. | decreases steady state error and improves stability |
| B. | rise time decreases |
| C. | transient response becomes poorer |
| D. | increases steady state error |
| Answer» A. decreases steady state error and improves stability | |
| Explanation: proportional integral and derivative controller is the controller that is the combinational controller that increases the speed of response, decreases steady state error and improves stability. | |
| 115. |
PI controller: |
| A. | decreases steady state error and improves stability |
| B. | rise time decreases |
| C. | transient response becomes poorer |
| D. | increases steady state error |
| Answer» C. transient response becomes poorer | |
| Explanation: in proportional and integral controller which is the extension of the integral controller which improves the steady state response but transient response becomes poorer. | |
| 116. |
Proportional controller |
| A. | decreases steady state error and improves stability |
| B. | rise time decreases |
| C. | transient response becomes poorer |
| D. | increases steady state error |
| Answer» D. increases steady state error | |
| Explanation: proportional controller is the controller that is used in the system so that the output follows the input and increases steady state error. | |
| 117. |
Lead compensator increases bandwidth |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: lead compensator is similar to high pass filter and causes lead in the system and increases the speed of response of the system and hence increases bandwidth. | |
| 118. |
Lag compensator reduces |
| A. | position constant |
| B. | velocity constant |
| C. | position variable |
| D. | acceleration constant |
| Answer» B. velocity constant | |
| Explanation: lag compensator is the integral compensation that causes the lag in the response and reduces velocity constant. | |
| 119. |
A linear time invariant system is stable if : |
| A. | system in excited by the bounded input, the output is also bounded |
| B. | in the absence of input output tends zero |
| C. | both a and b |
| D. | system in excited by the bounded input, the output is not bounded |
| Answer» C. both a and b | |
| Explanation: a system is stable only if it is bibo stable and asymptotic stable. | |
| 120. |
Asymptotic stability is concerned with: |
| A. | a system under influence of input |
| B. | a system not under influence of input |
| C. | a system under influence of output |
| D. | a system not under influence of output |
| Answer» B. a system not under influence of input | |
| Explanation: asymptotic stability concerns a free system relative to its transient behavior. | |
| 121. |
Bounded input and Bounded output stability notion concerns with : |
| A. | a system under influence of input |
| B. | a system not under influence of input |
| C. | a system under influence of output |
| D. | a system not under influence of output |
| Answer» A. a system under influence of input | |
| Explanation: bibo stability concerns with the system that has input present. | |
| 122. |
If a system is given unbounded input then the system is: |
| A. | stable |
| B. | unstable |
| C. | not defined |
| D. | linear |
| Answer» C. not defined | |
| Explanation: if the system is given with the unbounded input then nothing can be clarified for the stability of the system. | |
| 123. |
Linear mathematical model applies to : |
| A. | linear systems |
| B. | stable systems |
| C. | unstable systems |
| D. | non-linear systems |
| Answer» B. stable systems | |
| Explanation: as the output exceeds certain magnitude then the linear mathematical model no longer applies. | |
| 124. |
For non-linear systems stability cannot be determined due to: |
| A. | possible existence of multiple equilibrium states |
| B. | no correspondence between bounded input and bounded output stability and asymptotic stability |
| C. | output may be bounded for the particular bounded input but may not be bounded for the bounded inputs |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: for non-linear systems stability cannot be determined as asymptotic stability and bibo stability concepts cannot be applied, existence of multiple states and unbounded output for many bounded inputs. | |
| 125. |
If the impulse response in absolutely integrable then the system is : |
| A. | absolutely stable |
| B. | unstable |
| C. | linear |
| D. | stable |
| Answer» A. absolutely stable | |
| Explanation: the impulse response must be absolutely integrable for the system to absolutely stable. | |
| 126. |
The roots of the transfer function do not have any effect on the stability of the system. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: the roots of transfer function also determine the stability of system as they may be real, complex and may have multiplicity of various order. | |
| 127. |
Roots with higher multiplicity on the imaginary axis makes the system : |
| A. | absolutely stable |
| B. | unstable |
| C. | linear |
| D. | stable |
| Answer» B. unstable | |
| Explanation: repetitive roots on the imaginary axis makes the system unstable. | |
| 128. |
Roots on the imaginary axis makes the system : |
| A. | stable |
| B. | unstable |
| C. | marginally stable |
| D. | linear |
| Answer» C. marginally stable | |
| Explanation: roots on the imaginary axis makes the system marginally stable. | |
| 129. |
If root of the characteristic equation has positive real part the system is : |
| A. | stable |
| B. | unstable |
| C. | marginally stable |
| D. | linear |
| Answer» B. unstable | |
| Explanation: the impulse response of the system is infinite when the roots of the characteristic equation has positive real part. | |
| 130. |
A linear system can be classified as : |
| A. | absolutely stable |
| B. | conditionally stable |
| C. | unstable |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: a system can be stable, unstable and conditionally stable also. | |
| 131. |
is a quantitative measure of how fast the transients die out in the system. |
| A. | absolutely stable |
| B. | conditionally stable |
| C. | unstable |
| D. | relative stability |
| Answer» D. relative stability | |
| Explanation: relative stability may be measured by relative settling times of each root or pair of roots. | |
| 132. |
Root locus of s(s+2)+K(s+4) =0 is a circle. What are the coordinates of the center of this circle? |
| A. | -2,0 |
| B. | -3,0 |
| C. | -4,0 |
| D. | -5,0 |
| Answer» C. -4,0 | |
| Explanation: s(s+2)+k(s+4) =0 | |
| 133. |
The main objective of drawing root locus plot is : |
| A. | to obtain a clear picture about the open loop poles and zeroes of the system |
| B. | to obtain a clear picture about the transient response of feedback system for various values of open loop gain k |
| C. | to determine sufficient condition for the value of ‘k’ that will make the feedback system unstable |
| D. | both b and c |
| Answer» D. both b and c | |
| Explanation: the main objective of drawing root locus plot is to obtain a clear picture about the transient response of feedback system for various values of open loop gain k and to determine sufficient condition for the value of ‘k’ that will make the feedback system unstable. | |
| 134. |
While increasing the value of gain K, the system becomes |
| A. | less stable |
| B. | more stable |
| C. | unstable |
| D. | absolute stable |
| Answer» A. less stable | |
| Explanation: damping factor is inversely proportional to gain on increasing gain it reduces hence makes the system less stable. | |
| 135. |
The addition of open loop poles pulls the root locus towards: |
| A. | the right and system becomes unstable |
| B. | imaginary axis and system becomes marginally stable |
| C. | the left and system becomes unstable |
| D. | the right and system becomes unstable |
| Answer» D. the right and system becomes unstable | |
| Explanation: the addition of open loop poles pulls the root locus towards the right and system becomes unstable. | |
| 136. |
Root locus is used to calculate: |
| A. | marginal stability |
| B. | absolute stability |
| C. | conditional stability |
| D. | relative stability |
| Answer» D. relative stability | |
| Explanation: root locus is used to calculate relative stability. | |
| 137. |
Routh Hurwitz criterion is better than root locus. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: root locus is better as it require less computation process. | |
| 138. |
Consider the following statements regarding root loci: |
| A. | all root loci start from the respective poles of g(s) h(s) |
| B. | all root loci end at the respective zeros of g(s) h(s) or go to infinity |
| C. | the root loci are symmetrical about the imaginary axis of the s-plane |
| D. | all root loci start and end from the respective poles of g(s) h(s) or go to infinity |
| Answer» B. all root loci end at the respective zeros of g(s) h(s) or go to infinity | |
| Explanation: all the root locus start at respective poles and end at zeroes. | |
| 139. |
Number of roots of characteristic equation is equal to the number of |
| A. | branches |
| B. | root |
| C. | stem |
| D. | poles |
| Answer» A. branches | |
| Explanation: number of roots of characteristic equation is equal to the number of branches. | |
| 140. |
Which of the following statements are correct? |
| A. | root locus is for the negative feedback systems |
| B. | complementary root locus is for the positive feedback systems |
| C. | root locus is for the negative feedback and complementary root locus is for the positive feedback systems |
| D. | complementary root locus is for the negative feedback systems |
| Answer» C. root locus is for the negative feedback and complementary root locus is for the positive feedback systems | |
| Explanation: root locus and complementary root locus are complementary to each other. | |
| 141. |
Consider the loop transfer function K(s+6)/(s+3)(s+5) In the root locus diagram the centroid will be located at: |
| A. | -4 |
| B. | -1 |
| C. | -2 |
| D. | -3 |
| Answer» C. -2 | |
| Explanation: centroid =sum of real part of open loop pole-sum of real part of open loop zeros/p-z. | |
| 142. |
Which one of the following applications software’s is used to obtain an accurate root locus for? |
| A. | lisp |
| B. | matlab |
| C. | dbase |
| D. | oracle |
| Answer» B. matlab | |
| Explanation: matlab stands for mathematics laboratory in which the input is in the form of the matrix and is the best software for drawing root locus. | |
| 143. |
Which one of the following is not the property of root loci? |
| A. | the root locus is symmetrical about imaginary axis |
| B. | they start from the open loop poles and terminate at the open loop zeroes |
| C. | the breakaway points are determined from dk/ds = 0 |
| D. | segments of the real axis are the part of the root locus if and only is the total number of real poles and zeroes to their right is odd. |
| Answer» A. the root locus is symmetrical about imaginary axis | |
| Explanation: the root locus is the locus traced due to the gain of the system with changing frequency and need not be symmetrical about origin. | |
| 144. |
The breakaway point calculated mathematically must always lie on the root locus. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: the breakaway point of the two | |
| 145. |
What is the number of the root locus segments which do not terminate on zeroes? |
| A. | the number of poles |
| B. | the number of zeroes |
| C. | the difference between the number of poles and zeroes |
| D. | the sum of the number of poles and the number of the zeroes |
| Answer» C. the difference between the number of poles and zeroes | |
| Explanation: the number of the root locus segments which do not lie on the root locus is the difference between the number of the poles and zeroes. | |
| 146. |
Which one of the following are correct? The root locus is the path of the roots of the characteristic equation traced out in the s- plane? |
| A. | as the input of the system is changed |
| B. | as the output of the system is changed |
| C. | as a system parameter is changed |
| D. | as the sensitivity is changed |
| Answer» C. as a system parameter is changed | |
| Explanation: the root locus is the locus of the change of the system parameters of the characteristic equation traced out in the s- plane. | |
| 147. |
If the gain of the system is reduced to a zero value, the roots of the system in the s- plane, |
| A. | coincide with zero |
| B. | move away from zero |
| C. | move away from poles |
| D. | coincide with the poles |
| Answer» D. coincide with the poles | |
| Explanation: the roots of the system in s plane coincides with the poles if the gain of the system is reduced to a value zero. | |
| 148. |
The addition of open loop zero pulls the root loci towards: |
| A. | the left and therefore system becomes more stable |
| B. | the right and therefore system becomes unstable |
| C. | imaginary axis and therefore system becomes marginally stable |
| D. | the left and therefore system becomes unstable |
| Answer» A. the left and therefore system becomes more stable | |
| Explanation: the system can become stable by reducing the damping and also by adding zeroes in the s plane and moving left of the s plane system becomes more stable. | |
| 149. |
If root loci plots of a particular control system do not intersect the imaginary axis at any point, then the gain margin of the system will be: |
| A. | 0 |
| B. | 0.707 |
| C. | 1 |
| D. | infinite |
| Answer» D. infinite | |
| Explanation: the gain margin is the inverse of the intersection of the root loci plot to the imaginary axis and if it does not intersect then the gain margin will be infinite. | |
| 150. |
When the number of poles is equal to the number of zeroes, how many branches of root locus tends towards infinity? |
| A. | 1 |
| B. | 2 |
| C. | 0 |
| D. | equal to number of zeroes |
| Answer» C. 0 | |
| Explanation: branches of the root locus is equal to the number of poles or zeroes which ever is greater and tends toward infinity when poles or zeroes are unequal. | |
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