Question

An object is placed in front of a convex lens of focal length 12cm, If the size of the image is half the size of the object , calculate the distance of the object from the lens.

Answer 1

Pls Refer the attachment

I hope this helps ( ╹▽╹ )

Answer 2

Answer:Now as we it is convex lens such that the formulae of it will be =1/v-1/u=1/f....(1)

Now it is also given that v=1/2u

Now let's take u=x such that v=1/2x

Now m=v/u

, m=1/2x/x(now x to x cancel down)

So m=1/2=v/u....(2)

Now use 2 in 1:

1/1/2x-1/x=1/12 (v=1/2x)

Then, 2/x-1/x=1/12 (now take L. C. M)

and we get, 2-1/x=1/12

, 1/x=1/12

, such that x=12cm.

Explanation: