The following graph depicts the inverse of magnification versus the distance between the object and lens data for a setup. The focal length of the lens used in the setup is

Options

A. 250 m
B. 0.004 m
C. 125 m
D. 0.002 m

Answer

B

Explanation

Magnification (m) =`+v/u`
From lens formula,
`1/v-1/u=1/("f)" rArr u/v-1=u/("f")rArr u/v=u/f+1`
`therefore` graph between `(u/v)` [ inverse of magnification] and u will be straight line with slope `1/f`
From graph, slope = 250
`therefore f=1/250m=0.004m`