The graph shown relationship between object distance and image distance for a equiconvex lens. Then focal length of the lens is `

Options

A. `0.50 pm0.05 cm`
B. `0.50 pm0.10 cm`
C. `5.00 pm0.05 cm`
D. `5.00 pm0.10 cm`

Answer

D

Explanation

In case of convex lens when object is kept at a distance twice the focal length then its real image is formed at the same distance on the other side of the lens.
Hence in this given case `2f=10 rArr f=5cm`.
If we assume that 1 cm on scale is divided in ten parts then least count of the scale becomes 0.1 cm which will also be equal to the maximum possible error in the measurement of u and v and the same error will be there in the measurement of focal length . Hence option (d) is correct.
length .