Question

An object 2cm high is placed at a distance of 16cm from a concave mirror as which produces a real image 3cm high.
(a) Find the position of the image.
(b) What is the focal length of the mirror

Answer 1

Answer:

Given O = 2cm

u = 16cm(-ve)

I = 3cm(-ve){Since image is real it is inverted)

⇒ -v/u = I / O

⇒ v = -1(I * u/o) = (-3cm * -16cm/2 cm) = 24 cm (-ve)

By relation 1/f = 1/u + 1/v

⇒1/f = 1/-16 + 1/-24

= 3 + 2/-48

=-5/48

⇒f = 48/5 (-ve) = 9.6 cm(-ve)

∵ C > u > f

⇒ Image formed is beyond C