A wire mesh consisting of very small squares is viewed at a distance of `8cm` through a magnifying converging lens of focal length `10 cm`, kept close to the eye. The magnification produced by the lens is:

Options

A. 5
B. 8
C. 10
D. 20

Answer

A

Explanation

`n=-8 cm. f=10cm`
As `(1)/(v)-(1)/(u)=(1)/(f)`
:. `(1)/(v)=(1)/(f)+(1)/(u)+(1)/(-8)=(1)/(10)-(1)/(8)=(4-5)/(40)=(-1)/(40)`
or, `v=-40cm`
Magnification produced by the lesn, `m(v)/(u)-(40)/(-8)=5`
This is a virtual inmage, erect and on the same side as the object.