11. What is the difference between Bluetooth and WI-Fi devices ?

1. 1. Bluetooth used 2.4 GHz radio frequency band whereas Wi-Fi can use 2.4 CHz or 5 GHz frequency band

   
   
   

   2. Bluetooth is used for wireless local area networks (WLAN) only whereas Wi-Fi is used for wireless wide area networks (WWAN) only

   
   
   

   3. When information is transmitted between two devices using bluetooth technology, the devices have to be in the line of sight of each other, but when Wi-Fi technology is used the devices need not be in the line of sight of each other

   
   
   

   4. The statements (a) and (b) given above are correct in this context

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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12. The diameter of optical fiber is

1. 1. 10^-3 cm

   
   
   

   2. 10^-4 cm

   
   
   

   3. 10^-2 cm

   
   
   

   4. 10^-5 cm

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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13. Optical fiber communication is generally preferred over general communication system because

1. 1. It is more efficient

   
   
   

   2. Of signal security

   
   
   

   3. Both (a) and (b)

   
   
   

   4. None of the above

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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14. A zener diode is also a p - n junction diode. It can be used as / an

1. 1. Full - wave rectifier

   
   
   

   2. AC voltage regulator

   
   
   

   3. DC voltage regulator

   
   
   

   4. Half - wave rectifier

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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15. At zero degree kelvin a piece of germanium

1. 1. Becomes semiconductor

   
   
   

   2. Becomes good conductor

   
   
   

   3. Becomes bad conductor

   
   
   

   4. None of the above

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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