Question

why a ray of light go undeviated through optical centre

Answer 1

We know that principal axis, both in mirrors and lenses, pass through the centre of curvature and optical centre respectively.
Going to the definition of the principal axis, you will find that the principal axis of the mirror or lenses is normal to the centre of curvature of optical centre.
It therefore, follows the laws of reflection. When the light rays are normal, we consider the incident angle to be 0° .
Then the reflected angle, being equal to the incident angle (according to the laws of reflection) is also 0°.
Thus, the angle of incident and angle of reflection is both 0°.
This results for the straight line.
Hence, the light rays passing through the centre of curvature of mirrors or optical centre of lenses passes undeviated.

Hope this will help you..

Answer 2

Answer:

1. The portion of a lens near the optical centre is like a very thin slab of glass.

2. Hence, a ray of light goes undeviated through the optical centre.

Explanation:

Optical Centre :

1. The point inside a lens on the principle axis, through which light rays pass without changing their path is called the optical centre of a lens.

2. It is denoted by O.