Q. Light from two coherent sources of the same amplitude A and wavelength $\lambda$ illuminates the screen. The intensity of the central maximum is $I_{0}.$ If the sources were incoherent, the intensity at the same point will be
A) $4I_{0}$
B) $2I_{0}$
C) $I_{0}$
D) $\frac{I_{0}}{2}$
Explanation
(d) The rays of light from two coherent sources superimpose each other on the screen forming alternate maxima (with maximum intensity $I_{0}$) and minima (with intensity zero). If two non-coherent sources superimpose, there will be no maxima and minima, instead the intensity will be $\frac{I_{0}}{2}$ throughout.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.