You want to coat the /inner/ surfaces of your windows (which have refractive index of 1.51) with a film in order to enhance the reflection of light back into the room so that you can use bulbs of lower wattage than usual. You find that MgF2, with n = 1.38, is not too expensive, so you decide to use it. Since incandescent home lightbulbs emit reddish light with a peak wavelength of approximately 660nm , you decide that this wavelength is the one to enhance in the light reflected back into the room.
A)What is the minimum thickness of film that you will need? t=?nm
B)If this layer seems too thin to be able to put on accurately, what other thicknesses would also work? Give only the three thinnest ones.
t2, t3, t4=nm ?