science light flashcards

What is light?

Light is a form of energy that travels as electromagnetic waves.

Transparent

A material that allows almost all light to pass through it and objects can be seen clearly.

Translucent

A material that allows some light to pass through it but objects appear blurry.

Opaque

A material that does not allow light to pass through it.

How does light travel?

Light travels in straight lines until it interacts with a material.

Where does visible light fall on the electromagnetic spectrum?

Visible light is a small portion of the electromagnetic spectrum between infrared and ultraviolet radiation.

What does ROYGBIV stand for?

Red, Orange, Yellow, Green, Blue, Indigo, Violet.

Which light waves can humans see?

The visible light spectrum (ROYGBIV).

Why do we see colour?

Objects absorb some wavelengths of light and reflect others. The reflected wavelengths are the colours we see.

What colour is white light?

White light contains all the colours of the visible spectrum.

What is incandescence?

The production of light by heating an object to a high temperature.

Example of incandescence

A traditional incandescent light bulb.

What is fluorescence?

The production of light when a substance absorbs ultraviolet light and immediately re-emits visible light.

Example of fluorescence

Fluorescent lamps and highlighter ink.

What is an LED?

A Light Emitting Diode that produces light when electricity passes through a semiconductor.

Advantages of LEDs

Energy efficient, long-lasting, and produce little heat.

What is chemiluminescence?

The production of light through a chemical reaction without significant heat.

Example of chemiluminescence

Glow sticks

What is bioluminescence?

The production of light by living organisms through chemical reactions.

Examples of bioluminescence

Fireflies, some jellyfish, and certain deep-sea creatures.

Luminous

An object that produces its own light.

Non-luminous

An object that does not produce its own light and must reflect light to be seen.

Is the Sun luminous or non-luminous?

luminous duh

Is the Moon luminous or non-luminous?

Non-luminous

What is reflection?

The bouncing of light off a surface.

Specular (regular) reflection

Reflection from a smooth surface where parallel rays remain parallel.

Diffuse reflection

Reflection from a rough surface where light is scattered in many directions.

Example of specular reflection

A mirror! Girl see your gorgeous self!!

Example of diffuse reflection

A painted wall.

What is the law of reflection?

The angle of incidence equals the angle of reflection.

Angle of incidence

The angle between the incoming ray and the normal.

Angle of reflection

The angle between the reflected ray and the normal.

What is the normal?

An imaginary line drawn perpendicular to the reflecting surface.

Plane mirror

A flat mirror that produces an upright, virtual image the same size as the object.

Convex mirror

A mirror that curves outward and produces smaller images with a wider field of view.

Concave mirror

A mirror that curves inward and can produce larger or smaller images depending on object position.

What does SALT stand for?

Size, Attitude, Location, Type.

SALT: Size in a plane mirror

Same size as the object.

SALT: Attitude in a plane mirror

Upright.

SALT: Location in a plane mirror

Same distance behind the mirror as the object is in front.

SALT: Type in a plane mirror

Virtual image.

What is a virtual image?

An image that cannot be projected onto a screen because light rays do not actually meet there.

How do you draw a ray model for a plane mirror?

Draw the object, mirror, incident ray, normal, reflected ray, and place the image the same distance behind the mirror as the object is in front.