Activity . Take a concave lens. Place it on a lens stand. Place a burning candle on one side of the lens.
Look through the lens from the other side and observe the image. Try to get the image on a screen, if possible. If not, observe the image directly through the lens. Note down the nature, relative size and approximate position of the image.
Move the candle away from the lens. Note the change in the size of the image. What happens to the size of the image when the candle is placed too far away from the lens. What conclusion can you draw from this Activity?
A concave lens will always give a virtual, erect and diminished image, irrespective of the position of the object.