36. Two sources of wave are called coherent if

1. 1. Both have the same amplitude of vibration

   
   
   

   2. Both produce waves of the same wavelength

   
   
   

   3. Both produce waves of the same wavelength having a constant phase difference

   
   
   

   4. Both produce waves having the same velocity

   
   
   

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   N/A

   Correct Option: C

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37. Line spectrum is given by

1. 1. Sun

   
   
   

   2. Mercury vapour lamp

   
   
   

   3. Candle

   
   
   

   4. Electric bulb

   
   
   

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   N/A

   Correct Option: B

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38. A monochromatic beam of light passes from a denser to a rarer medium as a result its

1. 1. Velocity increases

   
   
   

   2. Velocity decreases

   
   
   

   3. Frequency decreases

   
   
   

   4. Wavelength decreases

   
   
   

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   N/A

   Correct Option: A

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39. A convex lens made of a material of refractive index 1.5 and having a focal length of 10 cm is immersed in a liquid of refractive index 3.0 The lens will behave as a

1. 1. Converging lens of focal length 10 cm

   
   
   

   2. Diverging lens of focal length 10 cm

   
   
   

   3. Diverging lens of focal length 30 cm

   
   
   

   4. None of the above

   
   
   

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   N/A

   Correct Option: B

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40. Two plane mirrors are inclined at a certain angle. A ray of light coming parallel to one of the mirrors is rendered parallel to the second mirror after two reflections The inclination between the mirror is

1. 1. 60°

   
   
   

   2. 90°

   
   
   

   3. 45°

   
   
   

   4. 30°

   
   
   

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1. View Hint View Answer Discuss in Forum

   N/A

   Correct Option: A

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