Wave Mechanics Question 682
Question: A source producing sound of frequency 170 Hz is approaching a stationary observer with a velocity $ 17m{{s}^{-1}} $ . The apparent change in the wavelength of sound heard by the observer is (speed of sound in air $ =340m{{s}^{-1}} $ )
Options:
A) 0.1 m
B) 0.2 m
C) 0.4 m
D) 0.5 m
Show Answer
Answer:
Correct Answer: A
Solution:
[a] $ \lambda =\frac{v}{n}=\frac{340}{170}=2m $ , $ n’=\frac{340}{340-17}\times 170 $
$ n’=178.9,Hz $ Now $ \lambda ‘=\frac{v}{n’}=\frac{340}{178.9}=1.9 $
$ \Rightarrow ,\lambda -\lambda ‘=2-1.9=0.1 $
BETA
