Images and ray diagrams

• A real image from an object comes together to form an image on a “screen” - like the image formed on an eyes retina
• A virtual image is when the rays are diverging so the light from the object appears to be coming from a completely different place
• What are two examples of virtual images?

  • you look in a mirror you see a virtual image of your face because the object appears to be behind the mirror
  • You can get a virtual image when looking at an object through a magnifying lens. The virtual image looks bigger than the object actually is.
• When you describe an image, you need to say how big it is compared to the object, whether it is upright or inverted relative to the object and whether it’s real or virtual
• Ray diagram for an image through a convex lens

  
• Ray diagram for an image through a concave lens

  
• Concave lenses always create virtual images. The image is the right way up smaller than the object and on the same side of the lens as the object.
• Magnification = image height / object height