Miscellany

1993 AP Exam problem #6.

d) air-oil

e) 
constructive interference will occur if the film thickness is 1/4 wavelength, 3/4 wavelength, 5/4, etc.
so thickness*4/1, *4/3, *4/5, etc will give wavelength
1.0*10^-7 * 4/1 = 4 * 10^-7 m
1.0*10^-7 * 4/3 = 1.33 * 10^-7 m


visible light is from 4 * 10^-7 to 7* 10^-7 m (400 nm to 700 nm), so the only visible wavelengths that will be intensified is 4*10^-7 m or 400 nm