If one of two identical slits producing interference in Young's experiment is covered with glass, so that the light intensity passing through it is reduced to 50%, what happens?

(a) :Let the intensity through one of the slit be I1=I. So, intensity of light through the slit covered by glass I2=0.5I. Maximum intensity Imax=(√I1+√I2)² ⇒Imax=(√I+√0.5I)²=2.25I. Minimum intensity Imin=(√I1−√I2)² ⇒Imin=(√I−√0.5I)²=0.25I. Thus ratio of intensities Imax/Imin=2.25/0.25=9. (b) :If white light is used instead of monochromatic light, then a white fringe is observed at the center of the screen and the coloured fringes are formed at different positions of the screen.