Copy of optics quiz.docx

X-rays

Used in baggage screening.

ultraviolet light

Used for cancer treatment.

radio waves

Used in telecommunications.

infrared light

Used for theatre/concert effects.

microwaves

Used for heating food.

gamma rays

Used for medical imaging.

visible light

Used by DVD player remote control.

light ray

A line on a diagram representing the direction and path that light is travelling.

geometric optics

The use of light rays to determine how light behaves when it strikes objects.

incident light

The light emitted from a source that strikes an object.

transparent

When a material transmits all or almost all incident light; objects can be clearly seen through the material.

translucent

When a material transmits some incident light but absorbs or reflects the rest.

opaque

When a material does not transmit any incident light; all incident light is either absorbed or reflected.

image

Reproduction of an object through the use of light.

mirror

Any polished surface reflecting an image.

reflection

The bouncing back of light from a surface.

incident ray

The incoming ray that strikes a surface.

reflected ray

The ray that bounces off a reflective surface.

angle of incidence

The angle between the incident ray and the normal.

angle of refraction

The angle between the reflected ray and the normal.

critical angle

The angle of incidence that results in an angle of refraction of 90 degrees.

total internal reflection

The situation when the angle of incidence is greater than the critical angle.

converging lens

A lens that is thickest in the middle and causes incident parallel light rays to converge.

diverging lens

A lens that is thinnest in the middle and causes incident parallel light rays to spread apart.

optical centre

Point at the exact centre of the lens.

principal focus

The point on the principal axis of a lens where light rays parallel to the principal axis converge.

LED

Light produced as a result of an electric current flowing only in one direction.

conductor

Material that allows current to flow in either direction.

triboluminescence

The production of light as a result of friction.

bioluminescence

The production of light in living organisms as a result of a chemical reaction.

phosphorescence

The process of producing light by the absorption of UV light resulting in the emission of visible light for an extended period.

fluorescence

Immediate emission of visible light as a result of the absorption of UV light.

luminous

Producing its own light.

non-luminous

Object that does not produce its own light.

incandescence

The production of light as a result of high temperature.

electric discharge

The process of producing light by passing an electric current through a gas.

medium

Any physical substance through which energy can be transferred.

radiation

A method of energy transfer that does not require a medium.

visible light

The electromagnetic waves that the human eye can detect.

electromagnetic spectrum

The classification of electromagnetic waves by energy.