Ahelium-neon laser (λ=633nm) illuminates a diffraction grating. the distance between the two m=1 bright fringes is 35 cm on a screen 2.5 m behind the grating.

what is the spacing between slits of the grating?

Explanation:

d = Spacing between slits of the grating

= Wavelength = 633 nm

As there are two bright fringes they will equally dispose on the screen from the central point

We have the relation

Wavelength is given by

The spacing between slits of the grating is

prolly a beacuse the momentuem the car has increases while going down hill

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.