Short Answer. 1. This is a concave mirror of radius 200m, The object distance is 8cm. Draw a my diagram, state whether the image is real or virtual. Calculate the image distance and magnification, _n_j_~__ 2. This is a diverging lens with a focal length of 15cm The object distance is 20cm, Draw a ray diagram, state whether the image is real or virtual. Calculate the image distance and magnification, 3. Light of wavelength 680nm falls on two slits and produces an interference pattern in which the third order (m = 3) bright fringe is 38mm from the central fringe on a screen 2.8m away What is the separation distance of the two slits? 4' A photon is absorbed by an electron in the n ~ 2 level of hydrogen promoting it to the n = 4 level, What was the frequency of the photon? Problems. 1. A uniform, thin film of alcohol (n = 1.36) lies on a glass plate (n = 1.56). A light source whose wavelength can change is incident on the film. Constructive interference occurs at a wavelength of 655nm, destructive interference at 525nm. What is the minimum thickness of the film? (Hint, m is NOT equal to one here!) 2. A photon of momentum 3.53 X 10-28 kgm/s is emitted from a hydrogen atom. Find the initial and final states of the electron that emitted this photon. (The table on page 792 might be useful)