Question

The local length of a convex lens in 50 cm. if an object is kept at a distance of 75 cm from the lens, then find the image distance and magnificatoin produce by the lence​

Answer 1

Answer:

0.4

Explanation:

--------------------------------------------------------------------------------------------------------------

Given: Focal length (f) = 50cm

           Object distance (u) = 75cm

Assumption: Let the image distance be v.

                      Let the magnification be m.

Solution:

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  ANSWER

--------------------------------------------------------------------------------------------------------------

Answer 2

Answer:

Explanation: 1/f=1/v+1/u

                     1/-50=1/v+1/-75

                      1/-50+1/75=1/v

                      -75+50/3750=1/v

                      -1/150=1/v

                       v=-150

                       m=h/h'=v/u

                      -150/-75=v/u

                       v/u=2

                       m=2