Light and OpticsLight and Optics

Mirrors form images by reflecting Mirrors form images by reflecting light.light.

OpticsOptics

Optics is the study of visible light and the Optics is the study of visible light and the ways in which visible light interacts with ways in which visible light interacts with the eye to produce vision.the eye to produce vision.

Optics is also the application of knowledge Optics is also the application of knowledge about visible light to develop eyeglasses, about visible light to develop eyeglasses, mirrors, magnifying lenses, cameras, and mirrors, magnifying lenses, cameras, and lasers – these can extend vision or use lasers – these can extend vision or use light in different ways.light in different ways.

Mirrors use regular reflectionMirrors use regular reflection

• Light travels in straight lines.Light travels in straight lines.• Light rays bounce off objects in a very Light rays bounce off objects in a very

predictable way.predictable way.• If the light from a flashlight strikes a mirror, If the light from a flashlight strikes a mirror,

the angle is called the the angle is called the angle of incidenceangle of incidence. . • The angle at which the rays reflect off the The angle at which the rays reflect off the

mirror is called the mirror is called the angle of reflectionangle of reflection..• Both angles are the same degree of Both angles are the same degree of

measure.measure.

Law of ReflectionLaw of Reflection

The law of reflection states that the angle The law of reflection states that the angle of reflection equals the angle of incidence.of reflection equals the angle of incidence.

Ex: If the angle of incidence is 60Ex: If the angle of incidence is 60oo then then the angle of reflection will be 60the angle of reflection will be 60oo..

Regular reflection – reflection of parallel Regular reflection – reflection of parallel light rays all in the same direction.light rays all in the same direction.

Diffuse reflection – reflection of parallel Diffuse reflection – reflection of parallel light rays in many different directions.light rays in many different directions.

Flat mirrors and imagesFlat mirrors and images

An image is a picture of an object formed An image is a picture of an object formed by waves of light.by waves of light.

In a flat mirror your image looks just like In a flat mirror your image looks just like you – same size, same clothes, everything you – same size, same clothes, everything the same.the same.

However, if you raise your right hand, the However, if you raise your right hand, the “image” will appear to raise the left hand. “image” will appear to raise the left hand. This is because it is as if the “image” is a This is because it is as if the “image” is a person facing you.person facing you.

Concave MirrorsConcave Mirrors

Concave Mirrors are curved inward toward Concave Mirrors are curved inward toward the center (like the inside of a spoon).the center (like the inside of a spoon).

Parallel light rays reflecting off a concave Parallel light rays reflecting off a concave mirror move toward each other, then cross mirror move toward each other, then cross each other to move apart again.each other to move apart again.

Images in this type of mirror can appear Images in this type of mirror can appear larger, smaller, or even upside down larger, smaller, or even upside down depending on the curve of the mirror’s depending on the curve of the mirror’s surface.surface.

Convex MirrorsConvex Mirrors

Convex Mirrors are curved outward (like Convex Mirrors are curved outward (like the bottom of a spoon).the bottom of a spoon).

In this type of mirror, parallel light rays In this type of mirror, parallel light rays move away from each other.move away from each other.

The image in a convex mirror appears The image in a convex mirror appears smaller.smaller.