An object 4cm in size is placed at 25cm in front of a concave mirror
of focal length 15cm. At what distance from the mirror would a screen be
placed in order to obtain a sharp image? Find the nature and the size of the
image.
focal length = f = - 15 cm
object distance = u = -25 cm
image distance = v = ?
hi = ?
ho = 4 cm
Mirror formula,
1/v + 1/u = 1/f
Thus, to get image of object sharp it has to be placed at 37.5 cm
Size of image is 6 cm
As the height of object is more and negative, nature of image is real, inverted and magnified.