Calculate the radius of curvatuire of the concave lens based on the measured focal length.

 R₁ = (n -1) f

Explanation:

In geometric optics the focal length and the radius of curvature are related, for the case of a lens

          1 / f = (n₂-n₀) (1 / R₁ - 1 / R₂)

where f is the focal length, n₂ is the refractive index of the material, n₀ is the refractive index of the medium surrounding the material, R₁ and R₂ are the radius of curvature of each of the material's

In our case, the most common is that the lens is in the air, so n1 = 1, in many cases one of the surfaces is flat, so its radius of curvature R₂ = ∞.

     1 / f = (n-1) (1 / R₁)

we look for the radius of curvature R₁

    1 / R₁ = 1 / f (n-1)

     R₁ = (n -1) f

With this expression we can find the radius of curvature of a concave-plane lens

hail is a solid form of precipitation composed of large, layered ice particles called pellets that often have spherical shapes. this phenomenon occurs during thunderstorms in the could type known as cumulus

hope this you out ^w^

double the distance = divide strength by 4