Ex-4.6   
The uncertainity in the poisition of electron after it passes through the slit is reduced to width of the slit
 delx=a
The uncertainity in momentum = h/a
Position of landing(angle t) = sin t = tan t = delz/dely =(h/a)/2*pi*a= w/2*pi*a  
where w=wavelenghth
Rewriting  the above expression a*sint = w/(2*pi)
 which is similar to a*sint = w  (neglect 2*pi)as found out by first minimum in diffraction by a slit of width a 
 It proves a close connection between wave behaviour and uncertainity principle