86. The circuit shown in the given figure in resonates at
    
    

1. 1. all frequencies

   
   
   

   2. 0.5 rad/sec

   
   
   

   3. 5 rad/sec

   
   
   

   4. 1 rad/sec

   
   
   

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1. View Hint View Answer Discuss in Forum

   Input impedance of the circuit,
   

   Z = 10 +		1	||		4jω +	1
   		jω				jω

   
   
   

   = 10 +	[1 - 4ω2]
   	jω[2 - 4ω2]

   Correct Option: B

   Input impedance of the circuit,
   

   Z = 10 +		1	||		4jω +	1
   		jω				jω

   
   
   

   = 10 +	[1 - 4ω2]
   	jω[2 - 4ω2]

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87. For the circuit show in the (given figure) i(t) under steady state is
    
    

1. 1. zero

   
   
   

   2. 5

   
   
   

   3. 7.07 sin t

   
   
   

   4. 7.07 sin (t – 45°)

   
   
   

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1. View Hint View Answer Discuss in Forum

   d.c. voltage 5V would encounter an open circuit in the capacitor and hence the current is 0.
   
   

   For a.c , i(t) =	10 sin t
   	1 + j2 +	1
   		j

   
   

   =	10 sin t	=	10	sin (t - 45°)
   	1 + j		√2

   
   = 7.07 sin (t – 45°)
   

   Correct Option: D

   d.c. voltage 5V would encounter an open circuit in the capacitor and hence the current is 0.
   
   

   For a.c , i(t) =	10 sin t
   	1 + j2 +	1
   		j

   
   

   =	10 sin t	=	10	sin (t - 45°)
   	1 + j		√2

   
   = 7.07 sin (t – 45°)
   

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88. Switch S in the given figure is closed at t = 0. If v₂ (0) = 10 V and v_g (0) = 0 V respectively, voltage across the capacitors in steady state will be
    
    

1. 1. v₂ (∞) = v_g (∞) = 0

   
   
   

   2. v₂ (∞) = 2V, v_g (∞) = 8 V

   
   
   

   3. v₂ (∞) = v_g (∞) = 8 V

   
   
   

   4. v₂ (∞) = v_g (∞) = 2 V

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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89. In the given figure, the switch was closed for a long time before opening at t = 0. The voltage V_x at t = 0⁺ is
    
    

1. 1. 25 V

   
   
   

   2. 50 V

   
   
   

   3. – 50 V

   
   
   

   4. 0 V

   
   
   

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1. View Hint View Answer Discuss in Forum

   At t = 0⁺ , the circuit will be as shown below.
   
   I _L (0⁺) = 0
   Then V_i = – 50 V

   Correct Option: C

   At t = 0⁺ , the circuit will be as shown below.
   
   I _L (0⁺) = 0
   Then V_i = – 50 V

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90. In the circuit of given figure, assume that the diodes are ideal and meter is an average indicating ammeter. The ammeter will read
    
    

1. 1. 0.4 √2 A
      

   
   
   

   2. 0.4 A
      

   
   
   

   3. 0.8	A
      π

      
      

   
   
   

   4. 0.4	mA
      π

   
   
   

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1. View Hint View Answer Discuss in Forum

   The meter will read during positive half for halfwave rectifier.
   

   Vav =	Vm	=	4	=	0.4	mA.
   	πR		π10K		π

   
   

   Correct Option: D

   The meter will read during positive half for halfwave rectifier.
   

   Vav =	Vm	=	4	=	0.4	mA.
   	πR		π10K		π

   
   

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