Wavelength Conversion in Water: 640 nm Light & Wedge

[lha08]

Homework Statement

Light of wavelength 640 nm in water illuminates a glass (n = 1.5) wedge submerged in water (n = 1.33). If the distance between successive bright fringes is 6 mm.

Homework Equations

The Attempt at a Solution

I have a lot of trouble trying to convert the wavelength of light into the wavelength of water...but the rest i pretty much understand, just that little part that is really frustrating me.

 

[Doc Al]

I have a lot of trouble trying to convert the wavelength of light into the wavelength of water...but the rest i pretty much understand, just that little part that is really frustrating me.

You mean convert the wavelength of light in one medium to the wavelength it would have in another.

It's easiest if you always compare the wavelength in a medium to the wavelength in vacuum (n = 1). λ_n = λ/n. So, 640 nm = λ/1.33. To find the wavelength in glass, you need to figure out λ/1.5.