Reflection and Refraction Key Terms

Flashcards covering terms and definitions related to reflection, refraction, and other wave phenomena.

What is the angle of incidence (i)?

The angle of the wave approaching a boundary, measured between the ray and the normal.

What is the angle of reflection (r)?

The angle of the wave leaving a boundary after reflection, measured between the ray and the normal.

What is the angle of refraction (r)?

The angle of the wave leaving a boundary after refraction, measured between the ray and the normal.

What is the critical angle (c)?

The angle of incidence in a denser medium at which the angle of refraction in the less dense medium is 90 degrees.

What is dispersion?

The separation of white light into its constituent colours when it passes through a medium like a prism due to different amounts of refraction for each colour.

What is an incident ray?

The ray of light approaching a boundary.

What is the Law of Reflection?

States that the angle of incidence is equal to the angle of reflection (i = r).

What does laterally inverted mean?

A characteristic of the image formed by a plane mirror where the image is reversed left to right.

What is the normal?

A construction line perpendicular to the surface of a boundary, used to measure angles of incidence, reflection, and refraction.

What is an optical fibre?

A flexible, transparent fibre that transmits light signals along its length using total internal reflection, used for communication and in medicine.

What does optically dense mean?

A term describing a material with a higher refractive index where light travels slower.

What is a plane mirror?

A flat reflective surface.

What is a refracted ray?

The ray of light leaving a boundary after undergoing refraction.

What is refraction?

The change in direction of a wave caused by a change in its speed when it crosses a boundary between two different media.

What is the refractive index (n)?

A dimensionless number that describes how fast light travels through a medium, calculated as the ratio of the speed of light in a vacuum to the speed of light in the medium.

What is Snell's Law?

An equation relating the refractive index of a medium to the angles of incidence and refraction (n = sin i / sin r).

What is total internal reflection?

A phenomenon that occurs when light travelling from a denser medium to a less dense medium hits the boundary at an angle of incidence greater than the critical angle, causing all the light to be reflected back into the denser medium.

What does upright mean (regarding images)?

A characteristic of an image where it is oriented in the same direction as the object.

What is a virtual image?

An image formed where virtual rays appear to meet; it cannot be projected onto a screen.

What is a virtual ray?

A dashed line tracing back the path of a reflected or refracted ray to show where an image appears to be formed.

What is wavelength?

The distance between successive crests of a wave.