SHORT QUESTIONS Q.1 A person wets his eyeglass to clean them. As the water evaporates he notices that for a short time the glass become markedly more non reflecting. Explain. Q.2 A lens is coated to reduce reflection. What happens to the energy that had previously been reflected? Is it absorbed by the coating? Q.3 If interference between light waves of different frequencies is possible, one should observe light beats, just as one obtains sound beats from two sources of sound with slightly different frequencies. Discuss how one might experimentally look for this possibility. Q.4 What is the shape of interference fringes as seen on a screen perpendicular to the line joining the sources in Young's interference experiment if the source are (a) pinholes, (b) slits? Q.5 In Young's double slit experiment why must the slits be close and of same width? Q.6 In Young's double slit experiment why do we use monochromatic light ? If white light is used, how would the pattern chan...