Question

a thin lens is defined as one for which
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Answer 1

 A narrow lens is one in which the gap between the two surfaces is small in comparison to other axial distances, essentially making s2 = s'1. In the case of a thin lens in the air, Eqs.

A thin lens is one whose thickness (the distance between the two surfaces of the lens along the optical axis) is small in comparison to the radii of curvature of the lens surfaces. Thick lenses are defined as lenses with a thickness that is not insignificant.

The thin lens approximation reduces ray tracing computations by ignoring optical effects caused by lens thickness. In approaches like ray transfer matrix analysis, it's frequently used with the paraxial approximation.

Answer 2

• A thin lens is defined as one in which the separation of the two surfaces.
• Which is negligible when compared to other axial distances.
• The net power of a thin lens is simply the reciprocal of its focal length.
• The thin lens has two surfaces.
• Gaussian relations are used to describe the lens.
• Gaussian relations states that the lens is actually simpler than those for a single refracting surface.
• A scale drawing of the lenses will indicate suitable thicknesses.
• We have to scale the lenses to their original focal lengths.
• The equation for the thin lens is:

        $\frac{1}{s^{\prime}}-\frac{1}{s}=(n-1)\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}\right)=P_{1}+P_{2}=P=\frac{1}{f^{\prime}}=-\frac{1}{f}$