Saved Bookmarks
| 1. |
Read the following paragraph and answer the following questions : In a reaonance tube apparatus a tunning fork of unknown frequency after striking with a rubber pad is held near the open end of resonance tube. The airm column of resonance tube can be varied. For definite length of air column is resonance tube. the airm column of resonance tube can be varied. For definite length of air column in resonance tube, standing waves are set up due to superposition of sound arives travelling in oppositc directions. the smallest value of length of air column which intensity of sound is maximum is 10 cm. Take speed of sound 344 m/s.Find the number of times y_(1) + y_(2) = 0at x = 0 in 1 sec. |
|
Answer» 100 `y_(1) = A cos (- 100 pi t) = A cos( 100 pi t ) ` `y_(2) = A cos (-92 pi t ) = A cos (92 pi t )` y= `y_(1) + y_(2) = A [ cos 100 pi t + cos 92 pi t ]` When y = 0 `rArr cos 100 pi t = - cos 92 pi t ` cos `(100 pi t) = cos [ (2N + 1 ) pi - 92 pi t ]` `100 pi t = (2n + 1) pi - 92 PIT ` `t = ((2n + 1) pi)/(192 pi )= (2n + 1)/(192) ` `Delta t = t_(n+ 1)- t_(n) = (2n + 3)/(192) ` 1 = `(2n + 3)/(192) rArrn = 95 ` So CORRECT choice is (d). |
|