111. Consider the following statements: Laser is an acronym for light amplification by stimulated emission of radiation. In comparison to LED, it has:
     (i) Higher emission efficiency
     (ii) No tuning arrangements
     (iii) Narrow spectral width
     (iv) Provision for confinement Of the statements:
     

1. 1. (i), (iii) and (iv) are correct
      

   
   
   

   2. (i), (ii) and (iii) are correct
      

   
   
   

   3. (i) and (iii) are correct
      

   
   
   

   4. (i), (ii) and (iv) are correct

   
   
   

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   NA

   Correct Option: A

   NA

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112. The transmission path loss L in the free space between a communication satellite operating at a frequency f and at a distance d from the earth station is:
     

1. 1. Directly proportional to fd
      

   
   
   

   2. Directly proportional to f²d²
      

   
   
   

   3. Inversely proportional to f
      

   
   
   

   4. Directly proportional to f³d³

   
   
   

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   NA

   Correct Option: A

   NA

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113. To increase the radar range of ground and surface targets to see well beyond the normal radar horizon, the electromagnetic wave propagation adopted is:
     

1. 1. Ionospheric scatter
      

   
   
   

   2. Tropo scatter
      

   
   
   

   3. Ground wave propagation
      

   
   
   

   4. Duct

   
   
   

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   NA

   Correct Option: B

   NA

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114. The front end of an amplifier chain in a microwave communication system is kept immersed in liquid nitrogen to:
     

1. 1. Dissipate heat generated by amplifier
      
      

   
   
   

   2. Expand its noise figure
      

   
   
   

   3. Improve its noise figure
      

   
   
   

   4. Reduce the distortion produced by the amplifier

   
   
   

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   NA

   Correct Option: C

   NA

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115. A disadvantage of microstrips with respect to stripline circuit is that the former:
     

1. 1. Do not let themselves to be printed-circuit techniques
      

   
   
   

   2. Are more likely to radiate
      

   
   
   

   3. Are bulkier
      

   
   
   

   4. Are more expensive and complex to manufacture
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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