SEE, WHEN  A MONOCHROMATIC SOURCE OF LIGHT (OR WAVE) IS TRAVELLING IN A NON DISTURBING PATH THEN IT 'LL GO ON WITHOUT ANY STOPPAGE.

BUT IF IN IT'S NORMAL PATH A DISTURBANCE OR U CAN SAY OBSTACLE  WIL B DERE THEN IT'LL OBVIOUSLY CHANGE IT'S PATH..

THAT MEANS IT WILL BEND AROUND D CORNER OF DAT OBSTACLE. AND NOW THE NEW SHADOW IS CALLED 'GEOMETRICAL SHADOW". AND DIS IS CALLED DIFFRACTION ..........

REMEMBER INTENSTY OF DIS GEO. SHADOW DECREASES.

AND DIS COMPLETE THING IS CALLED DIFFRACTION ..

SIZE OF OBSTACLR SHUD B  OF D ORDER OF WAVELENGTH OF DAT WAVE...

V TAKE SMALL OBSTACLE. COZ WE DON'T OUR SHADOW (NEW ONE) TO B FAR AWAY....

DEPENDS ON SIZE..