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