A screen is placed 90 cm away from an object. The image of the object on the screen is formed by a convex lens at two different locations separated by 20 cm. Find the focal length of lens. A screen is placed 90 cm away from an object. The image of the object on the screen is formed by a convex lens at two different locations separated by 20 cm. Find the focal length of lens. November 8, 2020 Category: Chapter 9 - Ray Optics , MTG NEET Physics , Part 1 , Facebook Messenger WhatsApp Share this:TwitterFacebook Related