A) \[\frac{2u}{\lambda }\]
B) \[\frac{u}{\lambda }\]
C) \[\sqrt{u\lambda }\]
D) \[\frac{u}{2\lambda }\]
Correct Answer: A
Solution :
for first source \[{{n}_{1}}=n\left( \frac{v-u}{v} \right)=\left( 1-\frac{u}{v} \right)n\] for II nd source \[{{n}_{2}}=n\left( \frac{v+u}{v} \right)=\left( 1+\frac{u}{v} \right)n\] Beat freq. \[=\left| {{n}_{1}}-{{n}_{2}} \right|=n+\frac{nu}{v}-n+\frac{nu}{v}\] \[=\frac{2nu}{v}=2\frac{u}{\lambda }\] \[\left[ \because \,\,v=n\lambda \,\,\,\therefore \,\,\frac{1}{\lambda }=\frac{n}{v} \right]\]You need to login to perform this action.
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