81. The pressure of the earth's atmosphere at sea level is due to the

1. 1. Fact that most living things constantly breathe air

   
   
   

   2. Gravitational attraction of the earth for the atmosphere

   
   
   

   3. Evaporation of water from the seas and oceans

   
   
   

   4. Heating of the atmosphere by the sun

   
   
   

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1. View Hint View Answer Discuss in Forum

   N/A

   Correct Option: B

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82. Roadways are banked on curves so that

1. 1. The speeding vehicles may not fall inwards

   
   
   

   2. The frictional force between the road and vehicle may be decreased

   
   
   

   3. The wear and tear of tyre may be avoided

   
   
   

   4. The weight of the vehicle may be decreased

   
   
   

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   N/A

   Correct Option: C

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83. The pressure in a liquid at a given depth below the surface

1. 1. Is always exerted downward

   
   
   

   2. Is the same in all directions

   
   
   

   3. Equals the total weight of liquid above the depth

   
   
   

   4. Depends upon the amount of liquid below the depth

   
   
   

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1. View Hint View Answer Discuss in Forum

   N/A

   Correct Option: B

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84. Consider the following statements
    1. A geo-stationary satellite is at an approximate height of 10,000 km.
    2. FM transmission of music is a very good quality because the atmospheric or man made noises. Which are generally frequency variations can do little harm?
    Which of the statements give above is / are correct?

1. 1. 1 only

   
   
   

   2. 2 only

   
   
   

   3. Both 1 and 2

   
   
   

   4. Neither 1 not 2

   
   
   

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1. View Hint View Answer Discuss in Forum

   N/A

   Correct Option: B

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85. A body slides down a frictionless inclined plane when released from rest. Another body falls freely from the same height, then

1. 1. Both reach the ground together

   
   
   

   2. Body sliding down the plane will strike the ground first

   
   
   

   3. Both reach the ground with same acceleration

   
   
   

   4. Both reach the ground with the same speed

   
   
   

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1. View Hint View Answer Discuss in Forum

   N/A

   Correct Option: D

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