Mirrors

Question 1

Define the chief ray

Answer 1

The off axis ray which by definition passes through the centre of the aperture stop of an optical system

Question 2

Define the marginal ray

Answer 2

Will be directed to the edge if the entrance pupil, yet post refraction will pass through the point of the edge of the aperture stop (borderline)

Question 3

Define the field stop

Answer 3

A field stop is the aperture that limits the image size - determined by the angle between the optical axis..and the stop

Question 4

Define apparent magnification

Answer 4

How clear the image seems to be in the eye of the examiner - ratio of the image size used with a magnifier vs the object directly when viewed at 250mm, unaided magnifier..

Question 5

Define diffraction

Answer 5

At the edge of an aperture stop, wavefront is caused to be distorted as it emerges from it

Question 6

What is the result of a large aperture stop on diffraction

Answer 6

Limited diffraction, as there is only a small proportion at the edge of the aperture whereby the diffraction occurs

Question 7

Define point spread function

Answer 7

The phenomenon, taking into account real optical world whereby even in the absence of aberrations, due to the finite size of apertures, a small amount of diffraction will occur. Hence, it is defined as the optical image taking into account the level of diffraction present