question_answer 64)

  Draw ray diagrams showing the image formation by a concave lens when an object is placed (a) at the focus of the lens (b) between focus and twice the focal length of the lens (c) beyond twice the focal length of the lens

Answer:

                  (A) The image formed is virtual, erect, diminished in size and between and F when the object is placed at focus (b) The image formed is virtual, erect, diminished in size and between optical centre andfocus F when the object is placed between focus and twice the focal length of the lens. (c) The image formed is virtual, erect, diminished in size and between optical centre andfocus F when the object is placed beyond twice the focal length of the lens.