A coating is applied to a lens to minimize reflections The i

A coating is applied to a lens to minimize reflections. The index of refraction of the coating is 1.55, and that of the lens is 1.48. If the coating is 178.0 nm thick, what wavelength is minimally reflected for normal incidence in the lowest order?
nm

Light of wavelength 587.7 nm illuminates a slit of width 0.75 mm.

Solution

Wavelength  = 587.7 x10 ^-9 m

Slit width d = 0.75  x10 ^-3 m

Distance of the 1 st minimum from the central maximum y =0.85 x10 ^-3 m

We know condition for 1 st minimum   dsin =

For small angles d ( y/D ) =