Question

the focal length of a convex lens is 50 cm.If an object is kept at a distance of 75cm from the lens,then find the image distance and magnification produced by the lens​

Answer 1

Answer:

Image distance = 150 cm

magnification = - 2

Answer 2

Answer:

Focal length (f) = 50cm

Object distance (u) = 75cm

Assumption: Let the image distance be v.

Le the magnification be m.

We know,

1/f = 1/u + 1/v

=> 1/50 = 1/(-75) + 1/v

=> 1/50 = - 1/75 + 1/v

=> 1/50 + 1/75 = 1/v

=> (3 + 2)/150 = 1/v

=> 5/150 = 1/v

=> 1/30 = 1/v

=> 30 = v

So,the image is formed at distance of 30cm.

Magnification = - v/u

= - 30/(-75)

= 0.4