11. If an ideal centre-trapped 1 : 4 tansformer is loaded as shown in the figure, then impedance measured across the terminals AA would be
    
    

1. 1. 	3Z
      	16

      
      

   
   
   

   2. 	3Z
      	18

      
      

   
   
   

   3. 	2Z
      	3

      
      

   
   
   

   4. 	Z
      	6

      
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   ZAA = (2Z)		N1		2	+ Z .		N1		2	=	3Z
   		N2					N2				16

   
   

   Correct Option: A

   ZAA = (2Z)		N1		2	+ Z .		N1		2	=	3Z
   		N2					N2				16

   
   

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12. The circuit shown in Fig. (a) replaced by its Norton’s equivalent in Fig. (b) The value of will be
    
    

1. 1. 2.5 ∠ 45° A

   
   
   

   2. 5 ∠ 90° A

   
   
   

   3. 10 ∠– 90° A

   
   
   

   4. 15 ∠– 45° A

   
   
   

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1. View Hint View Answer Discuss in Forum

   I =	25
   	5 - j10 + j5

   
   

   =	25	= 2.5 ∠ 45° A
   	5 - 5j

   
   

   Correct Option: A

   I =	25
   	5 - j10 + j5

   
   

   =	25	= 2.5 ∠ 45° A
   	5 - 5j

   
   

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13. If i = – 10 e ^{– 2t}, then voltage of the source of the given circuit, V_s is given by
    
    

1. 1. – 10 e ^{– 2t}
      

   
   
   

   2. 1 – 10 e ^{– 2t}
      

   
   
   

   3. 20 e ^{– 2t}
      

   
   
   

   4. – 30 e ^{– 2t}

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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14. For the equivalent λ ≡ ∆ circuit shown in the given firgure, values of R_AB and R_BC are respectively
    
    

1. 1. 5 Ω and 15 Ω

   
   
   

   2. 15 Ω and 30 Ω

   
   
   

   3. 30 Ω and 5 Ω

   
   
   

   4. 20 Ω and 35 Ω

   
   
   

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1. View Hint View Answer Discuss in Forum

   RAB =	RA.RB + RC.RB + RC.RA
   	RC

   
   

   =	4.5 + 13.5 + 27	= 5 Ω
   	9

   
   

   And RBC =	RA RB + RC RB + RC RA
   	RA

   
   

   =	45	= 15 Ω
   	3

   
   

   Correct Option: A

   RAB =	RA.RB + RC.RB + RC.RA
   	RC

   
   

   =	4.5 + 13.5 + 27	= 5 Ω
   	9

   
   

   And RBC =	RA RB + RC RB + RC RA
   	RA

   
   

   =	45	= 15 Ω
   	3

   
   

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15. The circuit shown in the given figure is equivalent to a load of
    
    

1. 1. 	4	ohms
      	3

      
      

   
   
   

   2. 	8	ohms
      	3

      
      

   
   
   

   3. 4 ohms
      

   
   
   

   4. 2 ohms

   
   
   

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1. View Hint View Answer Discuss in Forum

   Applying KCL
   

   	V	+	V - 2I	= I
   	4		2

   
   

   ⇒	V	=	8	Ω
   	I		3

   Correct Option: B

   Applying KCL
   

   	V	+	V - 2I	= I
   	4		2

   
   

   ⇒	V	=	8	Ω
   	I		3

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