Question

A double convex lens is made of a material having refractive index 1.2. Both the surfaces of the lens are convex. If it is dipped into water of refractive index 1.33, it will behave like: 
 

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

Hint:

When the refractive index of the surrounding medium is greater than that of the lens material, the lens becomes divergent.

Answer 1

The Correct Option is B

The focal length of a lens is determined by the refractive index difference between the material of the lens and the medium around it. When the lens is dipped in water, the refractive index of the medium increases, reducing the refractive index difference and causing the lens to behave more like a divergent lens.