How Does Diffraction in Water Affect Light Angles Compared to Air?

[zzizi]

Homework Statement

Hi

Could someone explain to me... if a diffraction experiment that had a plane grating on it was submerged into water...why the diffracted light would produce extra angles that are wider and narrower than if the experiment had been carried in air?

Homework Equations

Snells law?

The Attempt at a Solution

Does it have something to do with refraction?

I would really appreciate an explanation, thanks.

 

[EinsteinKillr]

assuming that the frequency of the light being used does not change in or out of the water then the wavelength must change as a result of the differing speeds of light. i.e:

frequency = velocity / wavelength ($$\lambda$$)

so, solving for $$\lambda$$, $$\lambda$$ = v/f.

in a vacuum (or near vacuum, i.e. air) v = c. However, in water v = c/~1.3, resulting in a $$\lambda$$ which is significantly different.

so, your diffraction equations:

d sin ($$\theta$$) = m $$\lambda$$, and a sin($$\theta$$) = m$$\lambda$$

are now using significantly different values, resulting in significantly different values for $$\theta.$$

 

[zzizi]

Thank you so much.