41. In a rectangular waveguide there is one half-wave variation of electric field across the narrow dimension and two half-wave variations of electric field across the wider dimension. What is dominant mode?
    

1. 1. TM₁₂
      

   
   
   

   2. TE₂₁
      

   
   
   

   3. TE₁₂
      

   
   
   

   4. TM₂₁
      

   
   
   

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   NA

   Correct Option: D

   NA

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42. Arrange in ascending order of fc, cut off frequency of the waveguides in the following modes:
    

1. 1. TE₁₀ < TE₂₀ < TE₀₁ < TM₁₁
      

   
   
   

   2. TE₁₀ < TE₀₁ < TE₂₀ < TM₁₁
      

   
   
   

   3. TM₁₁ < TE₀₁ < TE₂₀ < TE₁₀
      

   
   
   

   4. TE₀₁ < TE₁₀ < TE₂₀ < TM₁₁

   
   
   

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   NA

   Correct Option: B

   NA

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43. A reflex klystron functions as:
    

1. 1. Microwave oscillator
      

   
   
   

   2. Microwave amplifier
      

   
   
   

   3. Both as microwave amplifier and oscillator
      

   
   
   

   4. A high gain cavity

   
   
   

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   NA

   Correct Option: A

   NA

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44. The modes in a reflex klystron:
    

1. 1. Give the same frequency but different transit times

   
   
   

   2. Result from excessive transit time across the resonator gap
      

   
   
   

   3. Are caused by spurious frequency modulation
      

   
   
   

   4. Are just for theoretical considerations

   
   
   

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   NA

   Correct Option: A

   NA

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45. The transmit time in the repeller space of a reflex klystron must be:
    

1. 1. n cycles

   
   
   

   2. 	n +	1		cycles
      		4

      
      

   
   
   

   3. 	n +	3		cycles
      		4

   
   
   

   4. 	n +	1		cycles
      		2

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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