Define.
1.Lense
2.Concave lense
3.convex lense
4.Principal axis
5.Focal length
6.Optical center
Answers
Answer:
1. a piece of glass or other transparent material with curved sides for concentrating or dispersing light rays, used singly (as in a magnifying glass) or with other lenses (as in a telescope).
2. A lens having at least one surface curved like the inner surface of a sphere.
3. An optical lens is generally made up of two spherical surfaces.
4. Optical axis, the straight line passing through the geometrical centre of a lens and joining the two centres of curvature of its surfaces. Sometimes the optical axis of a lens is called its principal axis.
5. the distance between the centre of a lens or curved mirror and its focus.
6. a point on the axis of a lens that is so located that any ray of light passing through it in passing through the lens suffers no net deviation and that may be within, without, or on either surface of the lens.
Answer:
Define lens:-
Lenses are basically magnifying glasses with curved sides. A lens is a piece of transparent glass which concentrates or disperses light rays when passes through them by refraction. Due to the magnifying property, lenses are used in telescopes and other magnifying devices. They are employed in cameras for gathering the light rays.
Define concave lens:-
A concave lens is a type of lens that diverges a straight light beam coming from the source to a diminished, upright, virtual image is known as a concave lens. It can form both real and virtual images. Concave lenses have at least one surface curved inside. A concave lens is also known as a diverging lens because they are shaped round inwards at the center and bulges outwards through the edges, making the light diverge on it. They are used for the treatment of myopia as they make faraway objects look smaller than they really are.
Define convex lens:-
Convex lenses converge parallel rays going in and convex lenses diverge rays.
Convex lenses converge parallel rays going in and convex lenses diverge rays.A convex lens is useful as a magnifying glass as it will produce a virtual enlarged image if the object is brought within the focal length. If the object is outside of the focal length, it will produce a real image that can be focused.With a convex lens, a virtual image is always produced.
Define Principal axis:-
A line passing through the center of the surface of a lens or spherical mirror and through the centers of curvature of all segments of the lens or mirror. Physics. one of three mutually perpendicular axes of a body about which the moment of inertia is maximum or minimum.
Define Focal length:-
The distance between the convex lens or a concave mirror and the focal point of a lens or mirror is called the focal length. It is the point where parallel rays of light meet or converge. The focal length varies with the sign (positive or negative) depending upon the nature of the lens and mirror(concave or convex).
Define optical centre:-
A point on the axis of a lens that is so located that any ray of light passing through it in passing through the lens suffers no net deviation and that may be within, without, or on either surface of the lens.