Astronomy-3

Question 1

Focal Length

Answer 1

The distance from lens to principle focus

Question 2

Principle Focus

Answer 2

It is a point in the principal axis of the convex lens where all the light rays parallel to the principle axis converge after passing through the lens

Question 3

Natural Adjustmet

Answer 3

This is the positioning of the objective and eyepiece to allow the eye to view a virtual image at infinity

Question 4

Angular Magnification

Answer 4

This is the ratio of the angle subtended by object and image

Question 5

Spherical Aberration

Answer 5

The blurring of an image due to unequal refraction of light by the spherical surface

Question 6

Chromatic Aberration

Answer 6

This occurs when wavelengths of colour are focused at different positions in the focal plane

Question 7

Angular Resolution

Answer 7

This is the smallest angle between close objects that can be seen clearly to be separate in a telescope

Question 8

Rayleigh Criterion

Answer 8

The minimum separation between two light sources that may be resolved into distinct objects

Question 9

Converging lens

Answer 9

A lens in which light rays that enter it parallel to its axis converge at a single pint in the opposite side

Question 10

Virtual image

Answer 10

An optical image formed from the apparent divergence of light rays from a point

Question 11

Real image

Answer 11

An optical image formed by the light rays passing through the light rays and can be collected in a screen