Binoculars and microscopes are frequently made with coated optics by adding a thin layer of transparent material to the lens surface as shown. One wants:
A) constructive interference between waves 1 and 2
B) destructive interference between waves 3 and 4
C) constructive interference between 3 and 4
D) the coating to be more transparent than the lens
E) the speed of light in the coating to be less than that in the lens

Question

Binoculars and microscopes are frequently made with coated optics by adding a thin layer of transparent material to the lens surface as shown. One wants: 
A) constructive interference between waves 1 and 2 
B) destructive interference between waves 3 and 4 
C) constructive interference between 3 and 4 
D) the coating to be more transparent than the lens 
E) the speed of light in the coating to be less than that in the lens

Quizplus · Accepted Answer

The coated optics in binoculars and microscopes work by creating constructive interference between the waves reflected off the thin layer of transparent material and the waves transmitted through the lens. This results in a brighter and clearer image for the viewer. Option A is incorrect because it mentions constructive interference between waves 1 and 2, which are not relevant in this context. Option B is incorrect because destructive interference would result in a dimmer and less clear image, which is not desirable for binoculars or microscopes. Option D is incorrect because the coating is meant to reduce reflections and increase light transmission, not to be more transparent than the lens. Option E is also incorrect because the speed of light in the coating should be greater than or equal to that in the lens to avoid any bending or distortion of the light.

Binoculars and Microscopes Are Frequently Made with Coated Optics by Adding