An effect analogous to two-slit interference can occur with sound waves, instead of light. in an open field, two speakers placed 1.30 m apart are powered by a single function generator producing sine waves at 1200-hz frequency. a student walks along a line 12.5 m away and parallel to the line between the speakers. she hears an alternating pattern of loud and quiet, due to constructive and destructive interference. what is : (a) the wavelength of this sound and (b) the distance between the central maximum and the first maximum (loud) position along this line

2.72 m

Explanation:

wavelength of sound λ = velocity / frequency

= 340 / 1200

= .2833 m

Distance of point of  first constructive interference

= λ D / d ( D is distance of the screen and d is distance between source of sound.

Here D = 12.5 m

d = 1.3 m

λ D / d= ( .2833 x 12.5) / 1.3

= 2.72 m

Distance of point of  first constructive interference = 2.72 m

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.