***Optics Homework 1 Flashcards

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.