Question

5. An object 1 cm high
produces a real image 1.5 cm
high, when placed at a
distance of 15 cm from
concave mirror calculate focal
length of mirror?​

Answer 1

Answer:

Height of the object (h) = 1cm

Height of the image (h') = -1.5cm

Object Distance (u) = -15cm

Image Distance (v) = ?

Focal length (f) = ?

=> m = h'/h = -v/u

-v = h'/h × u

= -1.5/1 × -15 = 22.5cm

v = -22.5cm

=> 1/v+1/u = 1/f (Mirror formula)

1/f = 1/-22.5 + 1/-15

= 1+1.5/-22.5 = 2.5/-22.5 = -0.11cm

f = 1/-0.11 = -9.09cm

I hope this helps you