A) \[256\times \frac{330}{325}-256\]
B) \[256-\frac{256\times 330}{335}\]
C) \[\frac{256\times 330}{325}-\frac{256\times 330}{325}\]
D) \[256\times \frac{335}{325}-256\]
Correct Answer: D
Solution :
In this case, the observer moves with the source. For direct sound, the velocity of source is the same as that of observer. The apparent frequency \[n\] is given by \[n=n\left( \frac{v-{{v}_{o}}}{v-{{v}_{s}}} \right)\] As \[{{v}_{o}}={{v}_{s}}\] \[\therefore \] \[n=n=256\,Hz\] For the reflected sound, the apparent frequency \[n\]is given by \[n=n\left( \frac{v-{{v}_{o}}}{v-{{v}_{s}}} \right)\] Here, \[n=256\text{ }Hz,\text{ }v=330\text{ }m/s\] Also, the observer moves in opposite direction to the source, so \[{{v}_{o}}=-5\,m/s\]and \[{{v}_{s}}=+\,5m/s\] \[\therefore \] \[n=256\left( \frac{330-(-5)}{330-(5)} \right)\] \[=256\times \frac{335}{325}\] Hence, beats per second \[=n-n\] \[=256\times \frac{335}{325}-256\]
You need to login to perform this action.
You will be redirected in
3 sec
