Light PS 9

Light Waves Electromagnetic waves Combination of electric and magnetic fields Do not require a medium to travel through Electromagnetic waves are transverse waves Travel at 300,000,000 m/s (3 x 108 m/s)

Light can… pass through anything that is transparent pass partially through anything that is translucent not pass through things that are opaque.

Light Waves Wavelength Frequency Measures the distance from crest to crest or trough to trough Wavelength determines the color of the light Frequency Measures the amount of waves that pass a point per second (Hz)

Light Waves Amplitude Speed Measures the distance from the rest position to a crest or trough Amplitude is the brightness of the light Speed How far a wave travels in one unit of time

Light Waves Formulas Speed = wavelength x frequency Frequency = speed ÷ wavelength Wavelength = speed ÷ frequency As wavelength increases, frequency decreases As frequency increases, wavelength decreases

Reflection Reflection A wave hits a surface through which it cannot pass; it bounces back Usually happens on opaque objects, but can also happen on translucent and transparent objects

Specular Reflection Reflection on a smooth surface

Diffused Reflection Reflection on an uneven surface

Reflection Plane Mirror: flat mirror that forms an image that is always right side up, same size as the real object, and same distance away from the mirror as the real object

Reflection Concave mirror: mirror that curves inward that forms images depending on the object’s position from the mirror. Ex: make-up mirror, flashlights, car headlights, telescopes

Concave Mirror Object farther away = image upside down and smaller Object medium distance away = image upside down and larger Object close = image right side up and larger

Reflection Convex mirror: mirror that curves outward and forms images that are always right side up and appear smaller and farther away than they really are.

Convex Mirror Examples

Refraction Refraction The bending of waves due to change in speed If white light is bent it turns into the visible spectrum If the visible spectrum is bent it turns back to white light

Refraction Concave lens a lens that curves inward and creates an image that spreads light to produce an image that is right side up

Concave Lens

Refraction Convex lens: a lens that curves outward, directing light to a center focal point

Refraction Object farther away = images upside down and smaller Object medium distance away = image upside down and larger Object close up = image upright and large

Viewed through a Convex lens at a medium distance Seed Pod Before Seed Pod Viewed through a Convex lens at a medium distance Convex Lens Used close up

Diffraction The bending of waves around the edge of a barrier

Interference Two waves meet Constructive Destructive