Question

An arrow 2.5 cm high is placed at a distance of 25 cm from a diverging mirror of focal length 20 cm. Find the nature, position and size of the image formed.

Answer 1

Explanation:

Given : h = 2.5 cm

u = - 25 cm

f = - 20 cm

Now,

1/v +1/u = 1/f

=> 1/v - 1/25 = - 1/20

=> 1/v = - 1/20 + 1/25

=> 1/v = - 5+4/100

=> v = - 100 cm

Now,

h'/h = -v/u

=> h'/2.5 = 100/25

=> h' = 2.5 X 4

= 10 cm

Nature : Virtual and Erect.

Position : -100 cm in the same side as the object

Size : 10 cm

Answer 2

Answer:

h1 = 2.5cm

u = -25cm

f = 20cm

1/f = 1/v + 1/u

1/20 = 1/v -1/25

1/v = 1/20 + 1/25

1/v = 9/100

v = 11.11 cm

m = h2/h1 = -v/u

h2/2.5 = -11.11/-25

h2 = 1.11 cm