21. When the frequency distribution is normal.

1. 1. Median, mode and mean are all different from one another

   
   
   

   2. Mean, mode and median are identical

   
   
   

   3. Mean is greater than mode

   
   
   

   4. Mean is greater than median

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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22. A noise level of 100 decibel would correspond to

1. 1. Just audible sound

   
   
   

   2. Ordinary conversation

   
   
   

   3. Sound from a noisy street

   
   
   

   4. Noise from a machine shop

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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23. Laplace's correction in the formula for the speed of sound given by Newton was needed because sound waves

1. 1. Are longitudinal

   
   
   

   2. Propagate isothermally

   
   
   

   3. Propagate adiabatically

   
   
   

   4. Have long wavelengths

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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24. There is no net transfer of energy by the particles of the medium in

1. 1. Longitudinal waves

   
   
   

   2. Transverse waves

   
   
   

   3. Progressive waves

   
   
   

   4. Stationary waves

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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25. In a stationary wave along a string the strain is

1. 1. Zero at nodes

   
   
   

   2. Maximum of nodes

   
   
   

   3. Maximum at anti nodes

   
   
   

   4. Constant every where

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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