Question

Define. Optical centre,focal length, principle axis,aperture..

Answer 1

Answer:

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Explanation:

The central point of the lens is known as the optical centre. Principal Axis. It is a line passing through the optical centre of the lens and perpendicular to both the faces of the lens.

Aperture. Aperture of a lens is the surface from which refraction of light takes place through the lens.!

Answer 2

Answer:

1). optical centre: a point in the lens on principal axis,such that any ray directed towards it emerges without deviation is called as optical centre of the lens..

2). Focal length: The distance of the principal focus from the optical centre of the lens is called focal length of the lense.

3). Principal axis: A line passing through the centre of the curvature of both the faces forming the lens is called the axis of the lens..

4). Aperture: Area of spherical surfaces of the lens across which refraction takes place is called aperture of lens..