Question

21. A concave mirror is used for image formation for different positions
of an object. What inferences can be drawn about the following when an
object is placed at a distance of 10 cm from the pole of a concave mirror
of focal length 15 cm ? (a) Position of the image (b) Size of the image (c)
Nature of the image Draw a labelled ray diagram to justify your inferences,
​

Answer 1

as mentioned the focal length of concave mirror is 15 cm and the object is placed at a distance of 10cm from the mirror means between pole and focus

a)so the image will be formed behind the mirror by Ray diagram.

and by mirror formula

1/f=1/v+1/u

1/-15= 1/v+(1/-10)

negative signs by using sign conventions for mirrors.

then v=+30 cm

b) size by magnification formula i.e v/u