76. A sonometer wire having a length of 50 cm is vibrating in the fundamental made with a frequency of 100 Hz. Which of the following is the type of propagating wave and its speed ?

1. 1. Longitudinal, 50 m / s

   
   
   

   2. Transverse, 50 m / s

   
   
   

   3. Longitudinal, 100 m / s

   
   
   

   4. Transverse, 100 m / s

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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77. 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 nor 2

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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78. What frequency range of E.M. waves are used for commercial FM radio ?

1. 1. 88 MHz to 108 MHz

   
   
   

   2. 88 kHz to 108 kHz

   
   
   

   3. 88 GHz to 108 GHz

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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79. When the same note is played on a sitar and flute, the sound produced can be distinguished from each other because of the difference in

1. 1. Pitch, loudness and quality

   
   
   

   2. Pitch and loudness

   
   
   

   3. Quality only

   
   
   

   4. Loudness only

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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80. An echo will be heard if the minimum distance between the source of sound and obstacle is

1. 1. 1 m

   
   
   

   2. 10 m

   
   
   

   3. 15 m

   
   
   

   4. 17 m

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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