91. In the following, pick out the linear systems.
    

    (i)	d2y(t)	+ a1	dy(t)	+ a2y(t) = u(t)
    	dt2		dt

    
    

    (ii) y	dy(t)	+ a1y(t)	= a2u(t)
    	dt

    
    

    (iii) 2	d2y	+ t	dy	+ t2y(t) =5
    	dt2		dt

    
    

1. 1. (i) and (ii)
      

   
   
   

   2. (i) only
      

   
   
   

   3. (i) and (iii)
      

   
   
   

   4. (ii) and (iii)

   
   
   

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1. View Hint View Answer Discuss in Forum

   For more detail refer the synopsis of signals and systems.

   Correct Option: C

   For more detail refer the synopsis of signals and systems.

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92. If stability error for step input and speed of response be the criterion for design, what controller would you recommend?
    

1. 1. P controller
      

   
   
   

   2. PD controller
      

   
   
   

   3. PI controller
      

   
   
   

   4. PID controller

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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93. An ON–OFF controller is a—
    

1. 1. P controller
      

   
   
   

   2. integral controller
      

   
   
   

   3. non-linear controller
      

   
   
   

   4. PID controller

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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94. The term ‘reset control’ refers to—
    

1. 1. proportional control
      

   
   
   

   2. integral control
      

   
   
   

   3. derivative control
      

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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95. The pole-zero plot given below is that of a/an—
    
    
    
    

1. 1. integrator
      

   
   
   

   2. PD controller
      

   
   
   

   3. PID controller
      

   
   
   

   4. lag-lead compensating network

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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