191. Reciprocity theorem is valid for—

1. 1. All linear networks

   
   
   

   2. All active elements.

   
   
   

   3. All linear and passive networks

   
   
   

   4. All linear, passive and bilateral networks.

   
   
   

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1. View Hint View Answer Discuss in Forum

   Reciprocity theorem is valid for all linear, passive and bilateral networks.

   Correct Option: D

   Reciprocity theorem is valid for all linear, passive and bilateral networks.

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192. An ideal voltage source and ideal current source are connected in parallel this circuit has—

1. 1. a Norton equivalent but not Thevenin equivalent.

   
   
   

   2. a Thevenin equivalent but not Norton equivalent.

   
   
   

   3. Both the Thevenin and Norton equivalent.

   
   
   

   4. Neither Thevenin nor Norton equivalent.
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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193. For the circuit shown in figure, the voltage V_s will be
     
     
     

1. 1. 12 V

   
   
   

   2. 8 V

   
   
   

   3. 4 V

   
   
   

   4. 13 V

   
   
   

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1. View Hint View Answer Discuss in Forum

   Current in branch EF =	1	1 amp
   	1

   
   

   Current in Branch AB =	VAB	=	2	= 2 amp
   	1Ω		1

   
   Current in branch CA = 1 + 2 = 3 amp.
   

   Current in CD =	VCD	=	ACA + VAB
   	1		1

   
   

   =	3 × 1 + 2 × 1
   	1

   
   = 5amp
   Current in branch GC = 5 + 3 = 8 amp
   Now, V_s = V_GC + V_CD
   = 1 × 8 + 1 × 5
   = 13 V
   

   
   

   Correct Option: D

   Current in branch EF =	1	1 amp
   	1

   
   

   Current in Branch AB =	VAB	=	2	= 2 amp
   	1Ω		1

   
   Current in branch CA = 1 + 2 = 3 amp.
   

   Current in CD =	VCD	=	ACA + VAB
   	1		1

   
   

   =	3 × 1 + 2 × 1
   	1

   
   = 5amp
   Current in branch GC = 5 + 3 = 8 amp
   Now, V_s = V_GC + V_CD
   = 1 × 8 + 1 × 5
   = 13 V
   

   
   

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194. The network shown, if i_R = (4 e^{— 3t} + 5 e^{— 4t}) amp and i _L (0) = 15 amp, then at t = 0 φ would be equal to—
     
     
     

1. 1. π

      2

   
   
   

   2. π

      3

   
   
   

   3. 2π

      3

   
   
   

   4. 2 π

   
   
   

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1. View Hint View Answer Discuss in Forum

   From given figure
   I_L = I_R + I₂ cos (t – φ)
   15 = (4e^–3t + 5e^–4t) + 12 cos (t – φ)
   at t = 0
   15 = 4 + 5 + 12 cos (–φ)
   or 15 – 9 = 12 cos φ
   or 6 = 12 cos φ
   

   or cos φ =	1
   	2

   
   

   or φ =	π
   	3

   
   

   
   

   Correct Option: B

   From given figure
   I_L = I_R + I₂ cos (t – φ)
   15 = (4e^–3t + 5e^–4t) + 12 cos (t – φ)
   at t = 0
   15 = 4 + 5 + 12 cos (–φ)
   or 15 – 9 = 12 cos φ
   or 6 = 12 cos φ
   

   or cos φ =	1
   	2

   
   

   or φ =	π
   	3

   
   

   
   

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195. Which of the following networks in the equivalent of the circuit shown in figure?
     
     
     
     

1. 1. 1

   
   
   

   2. 2

   
   
   

   3. 3

   
   
   

   4. 4

   
   
   

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1. View Hint View Answer Discuss in Forum

   This can be solved by using Star to Delta transformation.
   

   R12 =	R1R2 + R2R3 + R3R1
   	R3

   
   

   =	J1 × -J1 + (-J1) + (-J1)× (J1)
   	-J1

   
   

   =	J2 + J2- J2	= +J
   	-J

   
   

   R23 =	R1R2 + R2R3 + R3R1	=	-J2	= -J
   	R1		J

   
   

   R31 =	R1R2 + R2R3 + R3R1	=	-J2	= J
   	R2		J

   
   

   Correct Option: A

   This can be solved by using Star to Delta transformation.
   

   R12 =	R1R2 + R2R3 + R3R1
   	R3

   
   

   =	J1 × -J1 + (-J1) + (-J1)× (J1)
   	-J1

   
   

   =	J2 + J2- J2	= +J
   	-J

   
   

   R23 =	R1R2 + R2R3 + R3R1	=	-J2	= -J
   	R1		J

   
   

   R31 =	R1R2 + R2R3 + R3R1	=	-J2	= J
   	R2		J

   
   

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