A non-reflective coating that has a thickness of 198 nm (n = 1.45) is deposited on top of a substrate of glass (n = 1.50). What wavelength of visible light is most strongly transmitted if it is illuminated perpendicular to its surface?

The  wavelength is

Explanation:

From the question we are told that  

      The  thickness is

      The refractive  index of the non-reflective coating is    

       The  refractive  index of glass is

Generally the condition for  destructive  interference is mathematically represented as

Where is the angle of refraction which is  0° when the light is strongly transmitted

    and  n is the order maximum interference

        so  

at the point n =  1  

at  n =2  

Now we know that the wavelength range of visible light is  between

   So the wavelength of visible light that is been transmitted is  

c) up

hope this