146. The pressure exerted on the walls of the container by a gas is due to the fact that the gas molecules

1. 1. Lose their kinetic energy

   
   
   

   2. Stick to the walls

   
   
   

   3. Are accelerated towards the walls

   
   
   

   4. Change their momenta due to collision with the walls

   
   
   

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   N/A

   Correct Option: D

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147. Two blocks of ice when pressed together join to form one block because

1. 1. Of heat produced during pressing

   
   
   

   2. Of cold produced during pressing

   
   
   

   3. Melting point of ice increases with increase of pressure

   
   
   

   4. Melting point of ice decrease with increase of pressure

   
   
   

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   N/A

   Correct Option: D

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148. It is difficult to cook at high altitudes because

1. 1. There is less oxygen in the air

   
   
   

   2. Due to falling temperature, more heat has to be given

   
   
   

   3. Due to decrease in atmospheric pressure, the boiling point of water decreases

   
   
   

   4. Of high moisture content there

   
   
   

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   N/A

   Correct Option: C

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149. A large iceberg melts at the base but not at the top because

1. 1. The base of iceberg remains in warmer conditions

   
   
   

   2. Ice at the base contains impurities

   
   
   

   3. Higher pressure at the base lowers the melting point of ice

   
   
   

   4. Ice at the top is different kind

   
   
   

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   N/A

   Correct Option: C

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150. Which of the following statements is wrong ?

1. 1. Stefan's constant is the same for all black bodies

   
   
   

   2. Thermal radiations travel with the speed of 3 X 10⁸ ms ^-1

   
   
   

   3. Thermal radiations exhibit diffraction

   
   
   

   4. Stefan's law is applicable for all heated body

   
   
   

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   N/A

   Correct Option: D

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