#1 A dentist uses a curved mirror to view the back side of the teeth on the upper jaw. Suppose she wants an ereet image with a magnification of 2.5 when the mirror is 4 em from a tooth. (a.) Is a concave or convex mirror needed to make this virtual image? Explain how you determined your answer. (b.) Use ray tracing to estimate the mirror's focal length. Since we do not know the curvature of the mirror, it has been represented as a vertical line in the diagram below. For full points, you must explain the procedure you used to determine the focal length. You should end with a numerical estimate of the mirror's foeal length, but you must do this problem without using the mirror equation. Only a written explanation and your ray diagram will be accepted. If you do not print of this figure, yon must use gridded paper to get full points on this question. anon\\