Physics (AS & A Level) · May / June 2016 · Paper 12 · Question 28

Coherent light passes through a double slit, producing bright and dark fringes on a screen placed parallel to the plane of the double slit. The intensity of the light from each of the slits is initially the same. The intensity of the light passing through one of the slits in the double slit is now increased. The frequency of the light remains constant. What is the effect on the appearance of the fringes on the screen?

1. Aseparation of fringes: decreases; maximum intensity of dark fringes: no change
2. Bseparation of fringes: increases; maximum intensity of dark fringes: greater
3. Cseparation of fringes: no change; maximum intensity of dark fringes: greater
4. Dseparation of fringes: no change; maximum intensity of dark fringes: no change

As printed in the paper