Fresnel BiprismHardQuestion 20214
Question
Fresnel biprism is used to obtain two coherent sources because:
- AIt produces two independent light beams
- BIt refracts two portions of the same wavefront to produce virtual images of the source that act as coherent sourcesCorrect
- CIt reflects light like two mirrors
- DIt filters specific wavelengths
Correct answer
It refracts two portions of the same wavefront to produce virtual images of the source that act as coherent sources
Explanation
The prism's two halves refract the incoming wavefront from a single slit in slightly different directions. These two refracted beams overlap and interfere, as if coming from two virtual coherent sources.