Question

How does one engineer a lens to achieve a high N. A.?

1) by constructing a lens with a big refractive index
2) by constructing a lens with a high visibility
3) by designing a lens that can be placed very close to the specimen
4) by designing a lens that can be submerged in water
5) by designing a lens that can be submerged in oil

Answer 1

To achieve a high Numerical Aperture (N.A.) for a lens, several factors can be considered including constructing a lens with a big refractive index, designing a lens that can be submerged in oil, and designing a lens that can be placed very close to the specimen.

Step-by-step explanation:

To engineer a lens for achieving a high Numerical Aperture (N.A.), several factors can be considered:

1. Constructing a lens with a big refractive index. This means using a material with a high refractive index, which allows the lens to bend light more effectively and increase the N.A.
2. Designing a lens that can be submerged in oil. By using an immersion lens with oil, the refractive indices of the lens and oil match closely, reducing light scattering and increasing the maximum angle at which light can enter the lens. This improves the N.A. and resolution.
3. Designing a lens that can be placed very close to the specimen. By minimizing the air gap between the lens and specimen, which causes light scattering and reduces resolution, the N.A. can be increased.