Physics Waves

Sound waves are _____ waves.

longitudinal

Light waves are ___ waves.

transverse

Radio waves are _____ waves.

transverse

Gamma waves are _____ waves.

transverse

properties of Longitudal waves

Oscillations are parallel to the direction of energy transfer

Properties of Transverse waves

Oscillations perpendicular to the direction of energy transfer.

Peak

Highest point of a wave

Trough

Lowest point of a wave

Properties of waves

-Happen because of oscillation
-They carry energy from one point to another and can also carry information.
-There is no transfer of matter/particles through which they are travelling

oscillation

The process of repeating vibrations

Rarefaction

a part in a longitudinal wave where the particles are spread apart

Compression

The part of a longitudinal wave where the particles of the medium are close together.

Amplitude

the height of a wave from the origin to a peak, or from the origin to a trough

Wavelength

Horizontal distance between the peaks or between the troughs of two adjacent waves. Measured in metres

Frequency

The number of complete waves that pass a given point in a certain amount of time. Measured in Hertz (Hz)

1 megahertz

1 000 000 Hz

Time period

the time it takes for a source to complete one wave.

Time period equation

Time period = 1 / frequency

Wave equation

Wave speed(m/s)= Frequency(hz) * wavelength(m)

Wavefront

a surface over which the phase of the wave is constant.

If you are standing behind a moving object emitting sound, what will the sound sound like.

Low pitch, as the frequency is lower

If you are standing in front of a moving object emitting sound, what will the sound sound like.

High pitch, as the frequency is higher

3 Highest frequency wave on the electromagnetic spectrum

Gamma, x-rays, ultra violet

3 lowest frequency wave on the electromagnetic spectrum

radio, microwaves, infra-red

Uses of x -rays

observing bones and parts of the body

Dangers of x -rays

Can damage DNA in cells

Dangers of gamma rays

Cell mutation and cancer

Uses of gamma rays

Sterilising food and medical equipment
Cancer radiation treatment

Geiger counter

a device that uses a gas-filled metal tube to detect radiation

Danger of UV rays

Can damage surface skin cells, sunburn, blindness, skin cancer, premature skin aging

Uses of UV rays

tanning beds
detecting counterfeit notes

Radio wave uses and dangers

Uses - Communication
Hazards - None

Microwave uses and dangers

Uses - Cooking, communications
Hazards - Heat, kills cells

Infra-red uses

Heaters and night vision equipment

Normal

An imainary line perpendicular to a surface

incident ray

the ray that comes from an object and strikes a surface.

reflected ray

the light ray that bounces off a surface

incident angle

the angle between the incident ray and the normal

angle of refection

the angle between the reflected ray and normal to the surface

Refrective Index

The amount of bending that happens when light passes from one material to another

Refractive index equation

n = sin i / sin r

critical angle

the angle of incidence that produces an angle of refraction of 90 degrees. Refraction does not happen after this point.