A convex lens made up of glass of refractive index `1.5` is dippedin turn
(i) in a medium of refractive index `1.65`
(ii) in a medium of refractive index `1.33`
(a) Will it behave as converging or diverging lens in the two cases ?
(b) How will its focal length changes in the two media ?

Explanation

To solve the problem, we will analyze the behavior of a convex lens made of glass with a refractive index of \( \mu_l = 1.5 \) when placed in two different media with refractive indices \( \mu_{s1} = 1.65 \) and \( \mu_{s2} = 1.33 \). We will determine whether the lens behaves as a converging or diverging lens in each case and how its focal length changes.

### Step 1: Understanding the Lens Maker's Formula
The lens maker's formula relates the focal length \( f \) of a lens to the refractive indices of the lens and the surrounding medium, as well as the radii of curvature \( r_1 \) and \( r_2 \) of the lens surfaces:
\[ \frac{1}{f} = \left( \mu_l - \mu_s \right) \cdot \frac{1}{R} \]
where \( R = \frac{1}{r_1} + \frac{1}{r_2} \).
...