6. Sinusoidal oscillators are—
   

1. 1. stable
      

   
   
   

   2. unstable
      

   
   
   

   3. marginally stable
      

   
   
   

   4. conditionally stable

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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7. Which one of the four signals flow graphs shown in (A), (B), (C) and (D) represents the block diagram shown in given figure?Kindle Edition.
   
   
   

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

   On drawing the signal flow graph from the given block diagram, we get
   Hence alternative (A) is the correct answer.

   
   

   Correct Option: A

   On drawing the signal flow graph from the given block diagram, we get
   Hence alternative (A) is the correct answer.

   
   

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8. In a linear system, an input of 5 sin ωt produces an output of 10 cos ωt. The output corresponding to input 10 cos ωt will be equal to—
   

1. 1. + 5 sin ωt
      

   
   
   

   2. – 5 sin ωt
      

   
   
   

   3. + 20 sin ωt
      

   
   
   

   4. – 20 sin ωt

   
   
   

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1. View Hint View Answer Discuss in Forum

   Given
   it means the system is differentiator with ω = 2
   So with,
   ω = 2
   = – 10. ω sin ωt
   = – 10 × 2. sin ωt
   = – 20 sin ωt,

   Correct Option: D

   Given
   it means the system is differentiator with ω = 2
   So with,
   ω = 2
   = – 10. ω sin ωt
   = – 10 × 2. sin ωt
   = – 20 sin ωt,

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9. NA
   
   
   

1. 1. C	= G
      R

      
      

   
   
   

   2. C	=	G
      R		1 + H/2

      
      

   
   
   

   3. C	=	G
      R		(1 + H1) (1 + H2)

      
      

   
   
   

   4. C	=	G
      R		1 + H1 + H2

   
   
   

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1. View Hint View Answer Discuss in Forum

   From figure
   C = GR – CH₂
   C (1 + H₂) = GR
   

   C	=	G
   R		1 + H2

   From figure
   C = GR – CH₂
   C (1 + H₂) = GR
   

   C	=	G
   R		1 + H2

   
   

   Correct Option: B

   From figure
   C = GR – CH₂
   C (1 + H₂) = GR
   

   C	=	G
   R		1 + H2

   
   

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10. A linear second-order system with the transfer function
    

    G(s) =	49
    	s2 + 8s + 49

    
    is initially at rest and is subject to a step input signal. The response of the system will exhibit a peak overshoot of—
    

1. 1. 16%
      

   
   
   

   2. 9%
      

   
   
   

   3. 2%
      

   
   
   

   4. zero

   
   
   

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1. View Hint View Answer Discuss in Forum

   We know that maximum overshoot is given as
   M_p = e^{– ξπ}/√1 – ξ²
   

   From given T.F. = G	49
   	s2 + 8s + 49

   
   C.E. = s2 + 8s + 49
   on comparing this equation with the standard equation
   ωn^s + ω²_n = 0
   2 ξω_n and ω_n = 7
   or
   

   ξ =	8	=	8	= .57
   	2ωn		2 × 7

   
   

   % Mp = e	-3.14 × (0.57)2	× 100 = 2%
   	√1 - (0.57)2

   Correct Option: C

   We know that maximum overshoot is given as
   M_p = e^{– ξπ}/√1 – ξ²
   

   From given T.F. = G	49
   	s2 + 8s + 49

   
   C.E. = s2 + 8s + 49
   on comparing this equation with the standard equation
   ωn^s + ω²_n = 0
   2 ξω_n and ω_n = 7
   or
   

   ξ =	8	=	8	= .57
   	2ωn		2 × 7

   
   

   % Mp = e	-3.14 × (0.57)2	× 100 = 2%
   	√1 - (0.57)2

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