Question

A mirror forms an image which is 30 cm from an object and twice its height y must be mirror is situated

Answer 1

Since given the height of the image is twice the height of the image this is only possible with concave mirror when object is placed between focus and pole of the mirror.

Hence,

magnification, m = -v/u = 2

=> v = -2u

also given the distance between object and image is 30 cm, hence

-u + v = 30

=> -u - 2u = 30

=> -3u = 30

=> u = -10 cm

Hence the mirror should be situated 10 cm from the object.