Problem 7: [11 points] A magician wishes to create the illusion of a 2.74 m tall elephant. She plans to do this by using a 0.500 m tall model elephant and a spherical mirror to form a virtual image. (Sizes and distances are not to scale in the diagram below.) JD Audiense Curtain Model MirroI a) Should the mirror be concave or convex? b) If the model must be placed 3.00 m from the mirror in order to conceal it from the audience, what radius of curvature is needed? c) How far from the mirror will the image be formed? Solution Here, a) the mirror should be concave b) object distance , do = 3 m image distance is di di/3 = - 2.74/.5 di = -16.44 Using mirror formula 2/r = 1/di + 1/do 2/r = 1/3 - 1/16.44 r = 7.34 m the radius of the curvature is 7.34 m c) the image is formed at 16.44 m from the mirror .