A thin convex lens is used to form a real image of a bright point object. The aperture of the lens is small. A graph shown is obtained by plotting, a suitable parameter `y` against another suitable parameter `x`. If `f=` focal length of lens.
`u=` the object distance
`v=` image distance

Options

A. `(uv)tox`, `(u+v)toy`
B. `u+vtox`, `uvtoy`
C. `utox`, `(u)/(v)toy`
D. `(1)/(u)tox`, `(1)/(v)toy`

Answer

C

Explanation

At `y=0`, `x=f`
we know that `(1)/(v)-(1)/(-u)=(1)/(f)`
`(1)/(v)+(1)/(u)=(1)/(f)`……(`1`)
If `v=oo`, `u=f` and `u=oo`, `v=f` from equation
`(u)/(v)+1=(u)/(f)`
`(u)/(v)+(u)/(f)=-1` to from this equation `u=f`
`(u)/(v)=0`, Hence `(u)/(v)` denoted `y-"axis"` and
`u` denoted `x-"axis"`