wave_mechanics interference_and_superposition_of_waves Question 6

Question: Two sources of sound A and B produces the wave of 350 Hz, they vibrate in the same phase. The particle P is vibrating under the influence of these two waves, if the amplitudes at the point P produced by the two waves is 0.3 mm and 0.4 mm, then the resultant amplitude of the point P will be when AP ? BP = 25 cm and the velocity of sound is 350 m/sec

Options:

A) 0.7 mm

B) 0.1 mm

C) 0.2 mm

D) 0.5 mm

Show Answer

Answer:

Correct Answer: D

Solution:

$ \lambda =\frac{v}{n}=\frac{350}{350}=1m $ =100 cm Also path difference $ (\Delta x) $ between the waves at the point of observation is $ AP-BP=25cm $ .

Hence

Therefore $ \Delta \varphi =\frac{2\pi }{\lambda }(\Delta x)=\frac{2\pi }{1}\times ( \frac{25}{100} )=\frac{\pi }{2} $

Therefore $ A=\sqrt{{{(a _{1})}^{2}}+{{(a _{2})}^{2}}} $

$ = $

$ \sqrt{{{(0.3)}^{2}}+{{(0.4)}^{2}}} $ = 0.5 $ mm $