The graph between \(\frac 1u\) and \(\frac 1v\) for a thin convex lens in order to determine its focal length is plotted as shown in the figure. The refractive index of lens is 1.5, and its both the surfaces have the same radius of curvature R. The value of R will be______cm. (where u = object distance, v = image distance)
Lenses that are made by combining two spherical transparent surfaces are called spherical lenses. In general, there are two kinds of spherical lenses. Lenses that are made by joining two spherical surfaces that bulge outward are convex lenses, whereas lenses that are made by joining two spherical surfaces that curve inward are concave lenses.
Properties of Convex lens:
In this, the lenses are thicker in the middle and thinner at the edges.
They have a positive focal length.
It intersects the incident rays towards the principal axis
These lenses are used in the camera, focus sunlight, projector microscope, simple telescope, overhead projector, magnifying glasses, etc.
Properties of Concave lens:
These lenses are thinner in the middle and thicker at the edges.
They have a negative focal length.
It parts the incident rays away from the principal axis.
These are used in the glasses, spy holes, some telescopes in the doors, etc.
