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# Application of Concave and Convex Lenses

Application of concave and convex lenses are an important tool to understand the application of concave and convex lenses. These are based on the two laws: - one is the law of refraction and other is the law of reflection. The main use of lenses can be used to be focusing the light in one point or light separated in different path.

A lens is an optical device which passes the refracted light, and helps in either convergence or divergence the beam of light. A simple lens consists of a single optical element. Almost all lenses are spherical lenses, in which the two surfaces are parts of the surfaces of spheres. Each of these surfaces could be either convex or concave or even planar.

Convex lens or lenses which bulge out from the lens is called convex. Concave or basically these lenses are depressed inside and hence are called concave. It is important to note that the line joining between the centers of the spheres is called axis of the lens. Mainly the concave and convex lens axis move through the lens center, because of the way lens is making. Lenses making may be cutting in ground to give them various shape and size.

The central axis may not pass through the lens physical center without any diversion. If we study about the Plano lens –convex lens, a co-liner stream of light which passes through the lens gets converged. The distance between the lenses to the spot is called focal length of the lens; the common notation of focal length is ‘f’.

Convex-concave both lenses can be either +ve or –ve focus, it is very important both concave lens and convex lens depending on the relative curvatures of both surfaces. A negative lens has a comparative concave surface and it will be thinner at the mid of the periphery. In other side, A +ve lens has a comparative convex surface and will be thicker at the mid than at the periphery.

For the application of concave and convex-lenses it is important to understand the main equation of lens which is known as Lens maker’s equation. The focal length of the lens in air can be finding the formula from the lens maker’s equation.

P= $\frac{1}{f}=(n-1)(\frac{1}{R_{1}}-\frac{1}{R_{2}})+\frac{(n-1)d}{nR_{1}.R_{2}}$

Now the basic notations of the words are as follows:-

P is denote as the power of lens

f is denoted as the focal length of the lens,

n is denoted as refractive index of the lens material,

R1 is denoted as the radius of curvature all kind of the lens. The surface very near to the light source,

R2 is denoted as the radius of curvature of all kind of lens surface very far from the light source,

This formula is very useful in understanding and finding the terms related to the concave and convex lenses. The main application of concave and convex lenses is as follows:-

1) Convex and Concave lenses are generally used in both glasses and microscopes.
2) Both of the lenses are also used in better sight.
3) They are also used in cameras also

Apart from the above applications, there are various applications as well.