81. The propagation of TE₁₀ mode in a rectangular waveguide is used to excite a circular waveguide as shown in figure I and figure II. The mode excited in
    the circular waveguide of figure I and figure II will be respectively—
    

1. 1. TE₁₁ and TM₀₁

   
   
   

   2. TM₀₁ and TE₁₁

   
   
   

   3. TE₀₁ and TM₀₁

   
   
   

   4. TM₀₁ and TE₀₁
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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82. The input impedance of a λ 8 long short-circuited section of a lossless transmission line is—

1. 1. Zero

   
   
   

   2. Inductive

   
   
   

   3. Capacitive

   
   
   

   4. Infinite

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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83. A 3 µF capacitor is charged by a constant current of 2 µA for 6 seconds. The voltage across the capacitor at the end of charging will be—

1. 1. 3 V

   
   
   

   2. 4 V

   
   
   

   3. 6 V

   
   
   

   4. 9 V

   
   
   

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1. View Hint View Answer Discuss in Forum

   V =	q	=	it	=	2 × 10−6 × 6	= 4V
   	C		C		3 × 10−6

   Correct Option: B

   V =	q	=	it	=	2 × 10−6 × 6	= 4V
   	C		C		3 × 10−6

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84. A positive charge of Q coulomb is located at point A (0, 0, 3) and a negative charge of magnitude Q coulomb is located at point B (0, 0, – 3). The electric field intensity at point C (4, 0, 0) is in the—

1. 1. Negative x-direction

   
   
   

   2. Negative z-direction

   
   
   

   3. Positive x-direction

   
   
   

   4. Positive z-direction

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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85. Polystyrene has a relative permittivity of 2.7. If the wave is incident at an angle 'θ' of 30º from air on-to polystyrene, the angle of transmission will be nearly—

1. 1. 0.2º

   
   
   

   2. 2º

   
   
   

   3. 18º

   
   
   

   4. 48º

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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