Question

A combination of two lenses with power $1D$ and $2D$ is there what is the total power?

Answer 1

Hint:Firstly let's get some idea about lens. A lens is a transparent piece of material that is shaped to bend light rays in a particular way when they move through it, whether that means causing the rays to converge to a specific point or diverge as if from that point.

Complete step by step answer:
When we combine two lenses the overall focal length is infinite when the distance between the two lenses (\[d\]) equals the total of the individual focal lengths (\[{f_1}{\text{ }} + {\text{ }}{f_2}\]). The refracted light rays are now parallel to each other. When two lenses are combined, the first creates an image that is then used as the subject of the second lens.

The magnification of a mixture is the ratio of the final image's height to the object's height.The capacity of a lens to converge or diverge the ray of light falling on it is its strength. A lens with a short focal length has a lot of strength to converge or diverge a parallel light beam.

The Diopter is a unit of measurement for electricity (D) if the focal length of the lens is 1 m, its power is 1 Diopter. Consider two focal length lenses. When two thin lenses with powers of \[\;{P_1}\] and \[{P_2}\] are kept together, the combined power is:
Total Power ($P$) = ${P_1} + {P_2}$
$P = 1D + 2D$
$\therefore P = 3D$

Note:One of the most important principles of ray optics is the power of a lens. The ability of a lens to refract light that passes through it is proportional to its power. The converging ability of a convex lens is defined by its strength, while the diverging ability of a concave lens is defined by its diverging ability.