Monochromatic light illuminates a narrow slit which is 4m away from the screen. Two very narrow panel slits 0.5 mm apart are placed midway between the single slit and the screen to form interference fringes. If the spacing of 5 fringes is 10mm calculate the wavelength of light.
What would be the effect of
(a) Halving the distance between the double slit and the screen
(b) Halving the slit separation
(c) covering one of the slits
(d) using white light
