Question

${\huge{\bold{\red{\mathbb{Hëy...\\ Please solve this one}}}}}$

An object is kept at a distance of 100 cm from wall. Now a convex lens is placed between object and wall. If the size of image on wall is thrice the size of object. Find focal length of lens.

Answer 1

Please find the answer in the attachment.

Answer 2

here is your answer mate ....

let the height of object be x .
height of image will be 3x .

3x/x =v/u
3=v/u
v=3u

now.. it is given to us ..
v+u =100
u+3u = 100
4u = 100
u=100/4
u = 25

v = 100-25
v= 75

now.. putting lens formula
v=75
u=25

1/f = 1/v - 1/u
1/f = 1/75 - 1/25
1/f = 1-3 /75.
1/f = -2 / 75
f= 75/-2
f = - 37.5

so... focal length is -37.5 ....

don't forget to mark as brainliest....