HW 1 OPTICS

What was the primary idea behind Plato's theory of vision?

Extromission

What is the main source of light in vision?

Any object capable of emitting light

How are light rays defined?

Trajectories by which light is transported

What happens to light rays from a distant point source?

They are considered parallel

What is an extended source of light?

A large source with observable effects

What kind of source is a star from another solar system considered as (as seen from earth with the naked eye)?

Point source

What occurs at the interface between two different media?

Light is partially reflected and partially refracted

According to the law of reflection, the angle of incidence is equal to:

The angle of reflection

What does Snell's law describe?

The relationship between the angles of incidence and refraction

What is the principle of least time or Fermat's principle?

Light takes the path which requires the shortest time

How is the index of refraction (n) of a material defined?

The ratio of the speed of light in vacuum to the speed of light in the material

What is the effect of a higher index of refraction on light speed in a material?

Light travels slower in the material

What is total internal reflection?

Light is completely reflected within a medium when the angle of incidence exceeds the critical angle

What is the critical angle for total internal reflection?

The angle of incidence at which light is completely reflected

What phenomenon causes a mirage?

Refraction of light due to temperature gradients in the atmosphere

What does the law of reversibility state?

The path of light is reversible

What is dispersion in optics?

The separation of light into its component wavelengths

What is the Abbe number a measure of?

Dispersion of a material

According to the geometrical model, how does light travel?

In straight lines

What are the three available models for light?

Geometrical, wave, and particle

What phenomenon is best explained by the wave model of light?

Interference

What is a secondary source of light?

An object that reflects light from a primary source

What is one of the function of a prism in optics?

To disperse light

What is the primary function of a lens in an optical system?

To change the vergence of light

What is the optical axis of a lens?

The imaginary line connecting the centers of curvature of the two surfaces of the lens

What is the optical center (OC) of a lens?

The point on the lens that light passes through and is not deviated (not refracted)

What type of lenses create a single point focus?

Spherical lenses

What type of lenses create a focal line instead of a point focus?

Cylindrical lenses