1. The problem statement, all variables and given/known data An object and a screen are separated by 20 cm. A convex lens is placed between them, 5 cm from the object. In this position it causes a sharp image of the object to form on the screen. What is the focal length of the lens? 3. The attempt at a solution wouldn't it just be 5 cm since it is producing a sharp image on the screen? the distance from the object to the lense?