Coherent sources can be created by the division of:
STATEMENT-1 : Two coherent point sources of light having nonzero phase difference are seperated by small distance. Then on the perpendicular bisector of line segment joining both the point sources, constructive interference cannot be obtained. STATEMENT-2 : For two waves from coherent point sources to interfere constructively at a point, the magnitude of their phase difference at that point must be 2mπ ( where m is a nonnegative integer).