P4: Waves

Oscillations that are perpendicular to the direction of energy transfer. Particles move from side to side. The amplitude goes up an down while the wave moves from left to right.

Oscillations that are parallel to the direction of energy transfer. Particles move back and forth. Some parts of the wave are closer together (compression) and some are further apart (rarefaction)

angle of reflection

n=c/v

n= refractive index

c= velocity of light in a vacuum (3.0*10^8)

v= velocity of light in a substance

n1sinθ1=n2sinθ2

n1= incidence index

n2=refracted index

θ1= incident angle

θ2=refracted angle

the measure of the bending of the refracted angle when it goes from one medium to another

Optical fibres allow TIR because each time light bounces inside the fibre, the angle of incidence is greater than the critical angle. The glass must be on high purity as well.

Used in telecommunication, internet, messages, endoscopes,

When the angle of incidence is greater than the critical angle, this results in no light being lost

Real images are images that can be projected onto another medium

Images that cannot be projected onto another medium

radio - micro - infra - visible- UV- xray - gamma

Electromagnetic waves can also travel in vacuums like space as well as air, this is because electromagnetic waves do not need a medium.

• television broadcasts, mobile phones

• transverse

• safe because of long wavelengths

• transverse

• satellite tv and telephones

• high exposure can cause burns

• transverse

• Security, remotes, night-vision

• long exposure can cause eye damage

• transverse

• medicine

• radiation sickness, DNA mutations

Where all the points of the crest join

wave speed=frequency*wavelength

waves peed: m/s

frequency: Hz

wavelength:m

Sound waves

all electromagnetic waves (radio, microwave)

Crest: the highest point of the wave

trough: the lowest point of the wave

The distance of one peak to the next

The distance between the crest and the center of the wave

The wavefronts spread

Waves transfer energy from one place to another without transferring matter, it can be observed as sound and light. When they travel from one place to another, they vibrate and/or oscillate.

How many oscillations of a wave per time period

inverted (upside down)

Enlarged (bigger)

Diminished (smaller)

real or virtual

upright

Skin cancer, premature aging.

Thicker in the middle, when rays pass through a converging lens, they converge at the focal point.

The distance between the center of the lens to the focal point is called the focal length

Thinner in the middle