Question

If a glass lens is immersed in oil, what is the effect on focal length of lens?​

Answer 1

Answer:

Thus, the focal length of the lens will increase. When any lens or glass slab is immersed in a liquid whose refractive index is equal to that of lens, refractive index of lens will be equal to 1 relative to that liquid. The focal length of the lens in this case, will tend to infinity.

Answer 2

The following are answers to the above question -

• If a glass lens is immersed in oil, then the focal length of the lens increases.
• Since, the refractive index of oil is more than air, when the lens is immersed in oil then its focal length increases, and the lens starts showing opposite action.
• The convex lens which has a positive focal length becomes negative(diverging) and the concave lens which has a negative focal length becomes positive(converging).
• Since the power of the lens is inversely proportional to the focal length of the lens. So when it is immersed in oil, the power of the lens decreases.