Question

Refraction by spherical lenses.​

Answer 1

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Answer 2

HEYA, BUDDY !!

→ When the curved face of a refracting element is of a spherical shape, these lenses are defined as Spherical lenses. Spherical lenses are of two types: Convex lens and Concave lens. Convex lenses are types of lenses that have thick central portions and thin periphery. Concave lenses are types of lenses that have thin central portions and thick periphery. These lenses have a lot of uses across industries for their practical utility. From microscopes and telescopes to glasses and car mirrors, the general presence of these lenses or the fundamentals upon which they operate is virtually irreplaceable.

As we know , Principal Axis: It is a straight line, hypothetically drawn, that links the center of curvature of the lens and optical center. It is always perpendicular to the vertical axis. We can calculate and locate the principal focus of the lens on the principal axis.

→Optical Centre: It is the centre of the lens, which is determined geometrically. The optical centre generally lies on the principal axis. When the light passes through the optical centre, no deviation of light will take place.

→Centre Of Curvature: The lens is always a separate part of the sphere. So the actual centre of the sphere, from which the lens is derived, is termed as the Centre of curvature. In other words, the space in between the point at which rays of the lens meets and the lens itself is denoted as the Centre of curvature.

→ Principal Focus: We always consider incident rays as parallel to the principal axis. These rays, after striking the lens, either join or seem like joining at a certain point. That point at which the rays join or seem to join at is known as Principal focus. It is also termed as the Focal point. The focus is present on both sides of the lens.

→Focal Length: It is the intermediate path or distance that lies between the optical centre and principal focus. It is denoted by ‘f'. Commonly, the focal length of a concave lens will always be negative, and that of a convex lens will always be positive.