51. An effect of phase-lag compensation on servo system performance is that—
    

1. 1. for a given relative stability, the velocity constant is increased
      

   
   
   

   2. for a given relative stability, the velocity constant is decreased
      

   
   
   

   3. the bandwidth of the system is increased
      

   
   
   

   4. the time response is made faster

   
   
   

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1. View Hint View Answer Discuss in Forum

   The effect of phase-lag compensation on servo system is that for a given relative stability, the velocity constant is increased.

   Correct Option: A

   The effect of phase-lag compensation on servo system is that for a given relative stability, the velocity constant is increased.

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52. The block diagram shown below is equivalent to—
    
    
    

1. 1. Fig:- A
      

   
   
   

   2. Fig:- B
      

   
   
   

   3. Fig:- C
      

   
   
   

   4. Fig:- D
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   its equivalent block is

   
   

   Correct Option: B

   its equivalent block is

   
   

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53. The transfer function of a zero-order-hold system is—
    

1. 1. (1/s) (1 + e^–sT)
      

   
   
   

   2. (1/s) (1 – e^–sT)
      

   
   
   

   3. 1– (1/s) e^–sT
      

   
   
   

   4. 1 + (1/s) e^–sT

   
   
   

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1. View Hint View Answer Discuss in Forum

   Transfer function of zero order hold system is 1/s (1 – e_{– sT)}

   Correct Option: B

   Transfer function of zero order hold system is 1/s (1 – e_{– sT)}

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54. In the Bode-plot of a unit feedback control system, the value of phase of G (jω) at the gain crossover frequency is – 125º. The phase margin of the system is—
    

1. 1. – 125°
      

   
   
   

   2. – 55°
      

   
   
   

   3. 55°
      

   
   
   

   4. 125°

   
   
   

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1. View Hint View Answer Discuss in Forum

   Phase margin of system,
   φ_PM = 180° + ∠ G (jω) H (jω)|
   at gain crossover frequency
   φ_PM = 180° – 125°
   or
   φ_PM = 55°

   Correct Option: C

   Phase margin of system,
   φ_PM = 180° + ∠ G (jω) H (jω)|
   at gain crossover frequency
   φ_PM = 180° – 125°
   or
   φ_PM = 55°

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55. Consider a feedback control system with loop transfer function
    

    G(s) H(s) =	K(1 + 0·5s)
    	s(1 + s) (1 + 2s)

    
    The type of the closed loop system is—
    

1. 1. zero
      

   
   
   

   2. one
      

   
   
   

   3. two
      

   
   
   

   4. three

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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