A student measures the focal length of a convex lens by putting an object pin at a distance `u` from the lens and measuring the distance `v` of the image pin. The graph between `u` and `v` plotted by the student should look like

Options

A.
B.
C.
D.

Answer

2

Explanation

For real image u is (-)and
v is (+)and`(1)/(v)-(1)/(u)=(1)/(f)`constant