# Reflection and Mirrors - Mission RM7 Detailed Help

 Jack and Jill are doing the 'Concave Mirror Lab.' They place a light bulb a distance of 37.4 cm from a concave mirror with a focal length of 13.8 cm. What would be the corresponding image distance for such an object location? Enter your answer in the box, accurate to the second decimal place.
 The mirror equation relates the object distance (do), the image distance (di) and the focal length (f):   1 / do + 1 / di = 1 / f
 The mirror equation, with its three reciprocal terms, is a little awkward to work with. It's recommended that you begin this problem by performing an algebra step to rearrange the equation such that the image distance (the unknown) is by itself on the left side of the equation. Then substitute the two numerical values into the equation and use your calculator to evaluate the right side. Once done, the reciprocal of the image distance is equal to the number on your calculator. Take the reciprocal of this number to determine the image distance.
 The Minds On Physics program calculates answers accurate to the fourth decimal place. Your answer does not need to be that accurate. The program will allow you to have a 1 percent deviation from the right answer without being wrong. This means two things: 1) Enter your answer with at least three significant digits. 2) Do not round any numbers until your final calculation.