Question

the focal length of a converging mirror is 4cm. if the object of height 2cm is placed 9 cm from the mirror then find the image distance , nature and size of the image?​

Answer 1

Explanation:

focal length = f = - 4cm

height of object = + 2cm

object distance = u = - 9cm

image distance = v = ?

height of image = size = h' = ?

mirror formula,

1/v + 1/u = 1/f

1/v = 1/f - 1/u

= -1/4 - (-1/9)

= -1/4 + 1/9

= -9 + 4/36

= -5/36

v = 36/-5

= -7.2 cm

Hence,

the image is formed at a distance of 7.2 cm from the mirror.

Magnification = m

m = -v/u

= -(-7.2)/-9

= -0.8

As the magnification is negative , the image is real , inverted.

also,

m = h'/h

-0.8 = h'/2

h' = -1.6 cm

SIZE OF THE IMAGE IS 1.6 CM

Answer 2

natural size is 6cm

image distance is 11cm