A lens is a transparent piece of glass or plastic with at least one curved surface. It gets its name from the Latin word for "lentil" (a type of pulse used in cooking), but don't let that confuse you. There's no real reason for this other than that the most common kind of lens (called a convex lens) looks very much like a lentil! A lens works by refraction: it bends light rays as they pass through it so they change direction. (You can read a full explanation of why this happens in our article on the light.) That means the rays seem to come from a point that's closer or further away from where they actually originate—and that's what makes objects seen through a lens seem either bigger or smaller than they really are.

Want to access more content for free to prepare for your board exams? Visit http://www.learnsmartpakistan.org today to master the difficult skills and concepts!.com

Follow us on Facebook   / learnsmartpakistan  
Twitter: @KPLearning
Subscribe to our Youtube Channel:    / knowledgeplatformpk  
Visit our website as well http://www.knowledgeplatform.com/