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

In air $\frac{1}{f_0}=\left({\mu }_g-1\right)\left[\frac{1}{R_1}-\frac{1}{R_2}\right]$

In liquid ${\frac{1}{f}}_i=\left({ }_w{\mu }_g-1\right)\left[\frac{1}{R_1}-\frac{1}{R_2}\right]$ Therefore $\frac{1}{f_0}=\left(\frac{{\mu }_g-{\mu }_w}{{\mu }_w}\right)\left[\frac{1}{R_1}-\frac{1}{R_2}\right]$

If ${\mu }_g>{\mu }_w\Rightarrow$No change in nature of lens.  $\therefore$It will behave like a convergent lens in liquid.