Question

plz answer it faster and explain​

Answer 1

Answer:

Focal length of the lens, f = 30 cms

Convex Lens

'Since, the image is formed on the back side of the lens, then the lens is Convex Lens where image is formed Real and Inverted'.

Therefore height of image = - 10 cms

Explanation:

Given,

Position of object, u = -45

Position of Image, v = 90

'Since, the image is formed on the back side of the lens, then the lens is Convex Lens where image is formed Real and Inverted'.

By lens formula, we get,.

1/f = 1/v - 1/u  (lens formula)

therefore

1/f = 1/90 -(-1/45)

1/f = 1/90 + 1/45

1/f = 3/90   (after taking LCM)

therefore f = 90/3

Focal length of the lens, f = 30 cms

We know,

Magnification, m = height of image, h' /height of object, h = Position of image, v / Position of object, u

m = h'/h = v / u

So,

height of image/5 = 90/45

=> Height of image, h' = 90/9 = 10 cm

Since, the image is inverted and real, hence its height will be in negative (by new sign convention).

Therefore height of image = - 10 cms

NOTE : THE EXPLANATION IS GIVEN IN THE ATTACHMENT. KINDLY REFER TO THAT ALSO.