Electrical Engineering MCQ Question Papers: Campus Placement

Subject: Control System 11

**Part 5: List for questions and answers of Control System II**

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**Q1. The value of ‘a’ to give phase margin = 45° will be G(s) = (as+1)/s²**

**a) 0.707**

**b) 1.414**

**c) 1.18**

**d) 0.9**

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**Q2. In polar plots if the critical point ‘-1+j0’ is enclosed then the system is ——–**

**a) Stable**

**b) Unstable**

**c) Marginally stable**

**d) Critical stable**

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**Q3. Resonant peak of a marginally stable system is**

**a) 0**

**b) Finite value**

**c) Infinite**

**d) Any of the above**

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**Q4. What is the effect of gain margin when the system gain is doubled?**

**a) 2 times**

**b) 1/2 times**

**c) Remains unaffected**

**d) None of the above**

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**Q5. A open loop transfer function is given as G(s) = (s+2)/(s+1)(s-1). Find the number of ****encirclements about ‘-1+j0’?**

**a) 1**

**b) 0**

**c) 2**

**d) 3**

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**Q6. Find the stability for the following transfer function? G(s) = 50/s(s+5)**

**a) Unstable**

**b) Marginally stable**

**c) Stable**

**d) Critically stable **

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**Q7. Find the corner frequency for the following transfer function? G(s) = 1/(s+2)**

**a) 2 rad/s**

**b) 1/2 rad/s**

**c) 4 rad/s**

**d) 1/4 rad/s**

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**Q8. Error at corner frequency ?cf of first order system is ——-**

**a) ±1 db**

**b) ±2 db**

**c) ±3 db**

**d) ±4 db**

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**Q9. The maximum phase lag occurs at the ——————- of the two corner frequencies?**

**a) Arithmetic mean**

**b) Geometric mean**

**c) Either 1 or 2**

**d) None of the above**

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**Q10. If the transfer function of a phase lead compensator is (s+a)/(s+b) and that of a lag ****compensator is (s+p)/(s+q), then which one of the following sets of conditions must be ****satisfied?**

**a) A greater than b, p greater than q**

**b) A greater than b, p less than q**

**c) A greater than b, p less than q**

**d) A less than b, p greater than q**

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**Q11. The compensator G(s) = 5(1 + 0.3s)/(1 + 0.1s) would provide a maximum phase shift of**

**a) 20°**

**b) 45°**

**c) 30°**

**d) 60°**

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**Q12. Consider the following statements for phase lead compensation:**

**a) Phase lead compensation shifts the gain crossover frequency to the right**

**b) The maximum phase lag occurs at the arithmetic mean of the two corner**

**frequencies**

**c) Both 1 and 2**

**d) Nether 1 nor 2 **

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**Q13. With regard to filtering property, the lead compensator is**

**a) Low pass filter**

**b) Band pass filter**

**c) High pass filter**

**d) Band reject filter**

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**Q14. A controller transfer function is given by C(s) = (1+2s)/(1+0.2s). What is its nature and ****parameter?**

**a) Lag compensator, ß = 10**

**b) Lag compensator, ß = 2**

**c) Lead compensator, a = 0.2**

**d) Lead compensator, a = 0.1**

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**Q15.Which of the following is/are represents the lead compensator?**

**a) (s+2)/(s+1)**

**b) (s+2)/(s+5)**

**c) (s+5)/(s+6)**

**d) Both 2 and 3**

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**Q16. Which of the following is/are represents the lag compensator?**

**a) (s+2)/(s+1)**

**b) (s+2)/(s+5)**

**c) (s+5)/(s+6)**

**d) Both 1 and 2**

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**Q17. The transfer function of a phase lead compensator is given by: G(s) = (1 + 3Ts)/(1 + ****Ts)where T>0. What is the maximum phase shift provided by such a compensator?**

**a) 90°**

**b) 45°**

**c) 30°**

**d) 60°**

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**Q18. The following transfer function represents a phase-lead compensator?**

**a) (s+4)/(s+6)**

**b) (4s+2)/(6s+1)**

**c) (s+4)/(3s+6)**

**d) 1/s **

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**Q19. To achieve the optimum transient response, the indicating instruments are so ****designed as to**

**a) Be undammed**

**b) Be critically damped**

**c) Provide damping which is slightly less than the critical value**

**d) Provide damping which is slightly more than the critical value**

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**Q20. In the cauer-2 form of LC network———is series element and ——–is shunt element ****respectively?**

**a) L and C**

**b) C and L**

**c) L and L**

**d) C and C **

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**Part 5: List for questions and answers of Control System II**

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**Q1. Answer: d**

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**Q2. Answer: b**

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**Q3. Answer: c**

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**Q4. Answer: b**

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**Q5. Answer: a**

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**Q6. Answer: c**

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**Q7. Answer: a**

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**Q8. Answer: c**

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**Q9. Answer: b**

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**Q10. Answer: d**

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**Q11. Answer: c**

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**Q12. Answer: a**

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**Q13. Answer: c**

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**Q14. Answer: d**

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**Q15. Answer: d**

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**Q16. Answer: a**

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**Q17. Answer: c**

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**Q18. Answer: a**

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**Q19. Answer: c**

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**Q20. Answer: b**