76. If hole is bored along a diameter of the earth and a stone is dropped into the hole it will

1. 1. Reach the centre of the earth and stop there

   
   
   

   2. Reach the other side of the earth and stop there

   
   
   

   3. Execute S.H.M. about the centre of the earth

   
   
   

   4. Execute oscillatory, but not simple harmonic motion about the centre of earth

   
   
   

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   N/A

   Correct Option: C

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77. 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

   N/A

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78. 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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   N/A

   Correct Option: B

   N/A

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79. The relay satellite transmits the television programme continuously from one part of the world to another because its

1. 1. Period is greater than the period of rotation of the earth about its axis

   
   
   

   2. Period is less than the period of rotation of the earth about its axis

   
   
   

   3. Period is less than the period of rotation of the earth about its axis

   
   
   

   4. Mass is less than the mass of the earth

   
   
   

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   N/A

   Correct Option: C

   N/A

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80. 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

   N/A

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