Heat can be transferred via conduction and convection, and requires a medium

Light energy travels through the vacuum of outer space, so light does not require a medium; it is transferred through radiation

Shows wave characteristics

Electromagnetic waves do not rerquire a medium for transportation

AM/FM radio

TV signals

Cellphone communication

Radar

Astronomy

Telecommunications

Microwave ovens

Astronomy

Remote controls

Lasers

Heat direction

Keeps food warm

Astronomy

Physical Therapy

Human vision

Theatre/concert lighting

Rainbows

Visible lasers

Astronomy

Causes skin to tan

Stimulates production of Vitamin D

Kills bacteria in food and water

"Black" light

Ultraviolet lasers

Astronomy

Medical imaging

Security equipment

Cancer treatment

Astronomy

Cancer treatment

Astronomy

Product of some nuclear decay

Production of light as a by-product of a chemical reaction

Almost no heat is produced in this form.

Electronic device that allows an electric current to flow in only one direction

Achieved using semiconductors

When current flows in the allowed direction, the LED emits light

LED differs because it does not contain a filament and does not produce much heat as a by-product

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

Incident light is light emitted from a source that strikes an object

An image is a reproduction of an original object that is produced through the use of light

A mirror is any polished surface that exhibits reflection

Reflection is simply the bouncing back of light from any surface

What do most mirrors consist of?

A sheet of glass followed by a thin layer of reflective silver or aluminum.

How does reflection work?

Original incoming ray is called incident ray.

Ray that bounces off the mirror is called the reflected ray.

The normal is the line that is perpendicular to the reflecting mirror surface.

Normal is drawn at the point where the incident ray strikes the surface of the mirror.

The angle of incidence is the angle between the incident ray and the normal.

The angle of reflection is the angle between the reflected ray and the normal.

What are the laws of reflection?

Angle of incidence = angle of reflection

The incident ray, the reflected ray, and the normal all lie in the same plane.

What is specular reflection?

Specular reflection is the reflection of light off a smooth, shiny surface

What is diffuse reflection?

Diffuse reflection is the reflection of light off an irregular or dull surface. The reflected rays do not emerge parallel to each other, but are in fact scattered.

What happens when you look through a mirror?

Light travels in straight lines, so when your eyes detect reflected light, it is actually projected backwards in a straight line. This results in your brain thinking that there is a light source behind the mirror and that is where the light rays originate. There appears to be an apparent light source behind the mirror that results in seeing the image behind the mirror. There is no real light source behind the mirror, and this kind of image is actually a virtual image

What is a virtual image?

A virtual image is an image in which light does not actually arrive at or come from the image location. The light only appears to come from the image. Your eyes detect the light rays, but your brain determines where the image is located.

What observations can you make between an object and its image in a plane mirror?

The distance from the object to the mirror is the same as the distance from the image to the mirror.

The object-image line is perpendicular to the mirror surface.

A plane mirror divides the object-image line in half and is perpendicular to that line

What does the acronym SALT stand for?

S: Size of the image

A: Attitude ( upright or inverted or otherwise)

L: Location of the image

T: Type of image ( virtual or real)

What is a concave (converging) mirror?

A concave mirror is shaped like the surface of a sphere in which the inner surface is reflective

What is a convex (diverging ) mirror?

A convex mirror is shaped like part of the surface of a sphere in which the outer surface is reflective

What is the center of curvature?

The center of curvature is the center of the sphere, part of whose surface forms the curved mirror, labelled as C.

What is the principal axis?

The principal axis of the mirror is the line going through the center of curvature and the center of the mirror.

Where is the vertex?

The vertex is the point where the principal axis intersects the mirror. Labelled as V.

How does a concave mirror function?

Any light rays that are parallel to the principal axis will be reflected off the mirror through a single point. This point, where the parallel light rays converge is called the focus

How to locate images in a concave mirror?

A light ray parallel to the principal axis is reflected through the focus.

A light ray going through the center of curvature is reflected back onto itself

A ray through the focus will reflect parallel to the principal axis

A ray aimed at the vertex will follow the law of reflection.

Two  rays are sufficient to identify an image; 3rd is for confirmation.

What are some special cases for the image and object on a concave mirror?

An object beyond C has an image smaller, inverted, between C& F and is real.

An object at C will have an image the same size, inverted, at C, and real

An object between C & F will have an image larger, inverted, beyond C and real

An object at F will be infinitely large.

An object between F and V will result in a larger, upright, inside the mirror, and virtual.

What is a real image?

It is an image that can be seen on a screen as a result of light rays actually arriving at the image.

What are some uses for converging mirrors?

Car headlights, flashlights, searchlights. They all have light sources slightly inside the focus so that the reflected rays diverge slightly and illuminate a greater area.

How to locate images in a diverging (convex) mirror?

A ray parallel to the principal axis is reflected as if it had come through the focus

A ray aimed at the center of curvature is reflected back upon itself.

A ray aimed at the focus is reflected parallel to the principal axis.

Rays reflected off a convex mirror always diverge. Reflected rays from an object never cross in front of the mirror to form a real image. However, the human brain extrapolates these rays behind the mirror to where they appear to converge.

Convex mirrors show a wide range of view with their small virtual image.