A thin lens is made with as material having refractive index `mu=1.5.` both the sides are convex. It is dipped in water `(mu=1.33)`. It will behave like

Options

A. convergent lens
B. a divergent lens
C. a rectangular slab
D. a prism

Answer

A

Explanation

`1/f=(mu_L/mu_m-1)(1/R+1/R)`
`= ((1.5 xx3)/4-1)2/R = 1/(8).(2)/R=1/(4R)` The focal length is positive hence it is a convergent lens.