Question

How to find size of the image for convex mirror without knowing object distance ?

Answer 1

If you don't know the distance of the object then the image distance and the focal length will be given...

Now you can use mirror formula:-

1/v +1/u =1/f

Now you will put the value of f and v

Then:-

1/u = 1/v-1/f

Then by putting the value you will get the answer