(a) Draw a ray diagram to show the formation of image of an object placed between infinity and optical center of a concave lens.

(b) A concave lens of focal length 15 cm forms an image 10 cm from the lens. Calculate

(i) the distance of the object from the lens

(ii) the magnification for the image formed

(iii) the nature of the image formed -

(a) The Ray diagram to show the formation of image of an object which is placed between the infinity and optical center of a concave lens is as follows:

The image will be obtained in between the optical centre and focus. The nature of the image formed will be virtual, erect and diminished in the size

(b) Given: Focal length of concave lens, f = -15 cm

Image distance = -10 cm

Applying the lens formula:

Object distance, u = -30 cm

(ii) Magnification is given by the ratio of size of the image to the size of the object and can be written as follows:

m =

(iii) Since the magnification is positive and is less than 1, so the image formed will be erect and diminished in size.