Question

the focal length a convex lens when it immersed in kerosene ?

Answer 1

HERE IS UR ANSWER...

THE FOCAL LENGTH WILL INCREASE... SINCE THE REFRACTIVE INDEX OF LIQUID IS LESSER THAN THAT OF GLASS MEDIUM CHANGES THAT'S WHY FOCAL LENGTH WILL INCREASE.

Answer 2

The refractive index of the lens is usually measured with respect to air.

However, if the lens is placed in a medium other than air, the refractive index changes and there is also a change in the focal length.

Focal length (f) is inversely proportional to the refractive index (n).

Hence, when a convex lens is placed inside kerosene (whose refractive index is greater than air), the lens became a concave lens and started diverting the rays instead of converging them on one single point.