61. When an aeroplane attains a speed higher than the speed of sound in air a loud bang is heared. This is because

1. 1. It explodes

   
   
   

   2. Its wings vibrate so violently that the bang is heard

   
   
   

   3. The normal engine noises undergo a Doppler shift to generate the bang

   
   
   

   4. It produces a shock wave which is received as the bang

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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62. Match List - I (Electromagnetic wave) with List - II (Discoverer) and select the correct answer using the codes given below

    	List-I		List-II
    F	Infrared waves	1.	W. Roentgen
    G	Ultraviolet rays	2.	Newton
    H	X - rays	3.	Herschell
    J	Visible rays	4.	Ritter

    Code

    	F	G	H	J
    A.	1	2	3	4
    B.	3	4	1	2
    C.	3	4	2	1
    D.	4	3	1	2

1. 1. A.

   
   
   

   2. B.

   
   
   

   3. C.

   
   
   

   4. D.

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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63. Match List - I (type of electromagnetic radiation ) with List - II (corresponding wavelength ) and select the correct answer using the codes given below
    

    	List-I		List-II
    F	Radio waves	1.	4x10-7 - 7x10-7 m
    G	Uitraviolet waves	2.	10-11 - 10-9 m
    H	Visible light	3.	10-6 - 10-3 m
    J	X - rays	4.	10-3 - 10-5 m
    		5.	10-9 - 107 m

    Code

    	F	G	H	J
    A.	3	2	4	5
    B.	4	5	1	2
    C.	3	5	4	2
    D.	4	2	1	5

1. 1. A.

   
   
   

   2. B.

   
   
   

   3. C.

   
   
   

   4. D.

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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64. In a stationary wave all the particles of the medium

1. 1. Cross the mean position with different velocities at different instants

   
   
   

   2. Cross the mean position with different velocities at the same instant

   
   
   

   3. Cross the mean position with same velocity

   
   
   

   4. Cross the mean position with same speed

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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65. In vacuum, the speed of light

1. 1. Depends on its wavelength

   
   
   

   2. Depends on its frequency

   
   
   

   3. Depends on its intensity

   
   
   

   4. Neither depends on its wavelength, frequency nor intensity

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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