191. Total internal reflection of light is possible when light enters from

1. 1. Air to glass

   
   
   

   2. Vacuum to air

   
   
   

   3. Air to water

   
   
   

   4. Water to air

   
   
   

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1. View Hint View Answer Discuss in Forum

   N/A

   Correct Option: D

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192. An object is placed between two parallel mirrors. The number of images formed is

1. 1. 4

   
   
   

   2. 6

   
   
   

   3. 8

   
   
   

   4. Infinite

   
   
   

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   N/A

   Correct Option: D

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193. The angle of elevation of a cloud is 30°. A thunder is heard 4 seconds after the lightening is observed. What is the vertical height of the cloud (speed of sound is 300 m/s).

1. 1. 330 m

   
   
   

   2. 660 m

   
   
   

   3. 660 3 m

   
   
   

   4. 1320 m

   
   
   

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1. View Hint View Answer Discuss in Forum

   N/A

   Correct Option: B

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