Question

object 60 CM tall is placed on the principal axis of a convex lens and its 30 cm tall image is formed on the screen placed at a distance of 40 cm from the object what is the focal length of the lens​

Answer 1

here's ur answer

focal length is 26.67 cm aprox

Answer 2

Answer:

"According to the given details, we can take the value of h as 60 cm

H1 = -30 cm

V + u = 40 cm

H1/h = V/u

60/-30 = v/u

-2 = v/u

V = -2u

-2u = u = 40 cm

-u = 40 cm

U = -40 cm

V = -2 x -40

V = 80 cm

We need to find the focal length

1/F = 1/80 + 1/40

1/F = 1+ 2/80

1/F = 3/80 cm

F = 80/3

F = 26.67 cm

"

Explanation: