Geometrical optics

Question 1

Refractive index

Answer 1

The ratio of the speed of light in a vacuum (c) to the speed of light in a material (v)

Question 2

Optical density

Answer 2

A measure of the refracting power of a medium

Question 3

Normal

Answer 3

The line, which is perpendicular to the plane of the surface

Question 4

Angle of incidence

Answer 4

Angle between the normal to a surface and incident light ray

Question 5

Angle of refraction

Answer 5

The angle between the normal to the surface and the refracted light ray

Question 6

Snells law

Answer 6

The ratio of the sine of the angle of incidence in one medium to the sine of the angle of refraction in the other medium is constant

Question 7

Critical angle

Answer 7

The angle of incidence in the optically denser medium for which the angle of refraction in the optically less dense medium is 90*

Question 8

Refraction

Answer 8

The change in direction of a light ray due to a change in speed when light travels from one medium into the other of a different optical density

Question 9

Law of reflection

Answer 9

When light is reflected the angle of incidence is always equal to the angle of reflection

Question 10

Angle of reflection

Answer 10

The angle between the normal to a reflecting surface and the reflected light ray