Power of accommodation is the ability of the eye lens to focus near and far objects clearly on the retina by adjusting its focal length. Power of accommodation of the eye is limited. It implies the focal length of the eye lens cannot be reduced beyond certain minimum limit.
The eye is a crucial and among the most intricate sense organs that we have as humans. It aids in our ability to visualise objects as well as our perception of light, color, and depth. Structure of Human Eye Sclera: It is the outer covering, a protective tough white layer called the sclera (white part …
Definition : “The ratio of the velocity of light in a vacuum to its velocity in any medium.” The refractive index, also called the index of refraction, describes how fast light travels through the material. Refractive indexes have no dimensions. The refractive index is the proportion between the speed of light in a vacuum (C) …
Laws of Refraction of Light (i)The incident ray, refracted ray, and the normal to the interface of two media at the point of incidence all lie on the same plane.(ii)The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant. This is also known as Snell’s …
Lens formulaThe lens formula is , Where v = distance of the image formed from the optical center of the lens, u = the distance of the object from the optical centre of the lens f= the focal length of the lens.Magnification The ratio of the height of an image (hi) to the height of …
Definition “The reciprocal of its focal length is called Power of the lens.” It is represented by the letter P. The power P of a lens of focal length f (in m) is given by. Power of lens (P) = 1/f ( in m). The SI unit of power of a lens is ‘dioptre’. It …
Sign convection for Convex and Concave lens (i) Convex lenses have a positive focal length.(ii)The sign convention states that the focal length of a concave lens is negative. The incident light always moves from left to right because the item is always on the left side of the lens.(iii)All lengths from the right side of …
Concave Lenses (i)When an object is placed at infinity, Position of Image – at the focus. Nature of Image –highly diminished and point size. (ii)When an object is placed at a finite distance from the lens, Position of Image – between the optical centre and the focus . Nature of Image –Virtual, The size of …
Convex Lenses (i)When an object is placed at infinity, Position – at the focus. Nature – highly diminished and point size. (ii)Beyond the centre of curvature (C or, 2f) Position of the image – In between the centre of curvature( C or, 2f) and focus(f) Nature of image – Real, Inverted , diminished . (iii) …
Convex lenses are known as converging lenses because the rays converge after falling on the convex lens. The concave lens is known as a diverging lens because the rays diverge after falling on the concave lens. Image formation with concave and convex lenses as below :-
