Question

Plano convex relation in refractive index and focal length

Answer 1

Answer:f=R/(u-1)

Explanation:

Answer 2

Explanation:

Focal length of a single refracting curved surface with the formula:

(p=nR−nLR=1fp=nR−nLR=1f)

The focal power of a normal lens is calculated with the powers of the two surfaces p1 and p2 it consists of, together with an often negliged term adressing the lenses thickness D.

(p12=p1+p2−p1p2DnR1p12=p1+p2−p1p2DnR1)

This formula is called Gullstrand’s formula.

Let’s put in the first formula for p1 and p2

p12=n−1R+1−n−Rp12=n−1R+1−n−R

p12=2n−1Rp12=2n−1R

f12=R2(n−1)f12=R2(n−1)

The focal power is linearly dependent on the refractive index, so the focal length is inversely dependent as f~1/n.

Refractive index describes a glass element’s ability to bend particular wavelengths of light.

Focal length describes the distance between the film or pixel plane and the lens’ nodal or center point, the point at which light rays converge and spread again.