PHYSICS - WAVES

what do waves do

transfer energy from one place to another

what does the displacement measure

how far up or down a wave has moved / oscillated

where is the crest

the highest point on a wave

where is the trough

the lowest point on a wave

what are the two types of waves

transverse

longitudinal

what wave has its oscillations perpendicular to the direction of energy transfer

transverse

what wave has its oscillations parallel to the direction of energy transfer

longitudinal

what is the relationship to the angle of incidence and angle of reflection

angle of incidence = angle of reflection

are waves always reflected

no

what are some other things that happen to waves

absorbed

reflected

transmitted

where does specular reflection take place and what will it create

on flat surfaces making a clear image

where does diffuse reflection take place an what will it create

on bumpy surface making an unclear image

what is the point of incidence

the point on a surface where the ray hits

if a ray is shined into a denser medium NOT perpendicular what will happen to the ray

it will slow down and be refracted towards the normal

does the frequency always change or stay the same

stay the same

what is the order of the electromagnetic spectrum starting with the longest wavelength and going down

Radio waves

Microwaves

Infrared

Visible light

Ultra violet

X Rays

Gamma rays

what type of waves are electromagnetic waves

transverse

what speed do electromagnetic waves travel at in a vacuum

3 x 10⁸ m/s

what two waves can be used for communication

radio waves

microwaves

True or False : radio waves have the shortest wavelength and the biggest frequency

False - they have the the longest wavelength and the lowest frequency

what are the three types of radio waves

long waves

short waves

very short waves

do microwaves and infrared waves have longer wavelengths then visible light

yes

where is infrared radiation emitted from

any object that has thermal energy

what can be used to transmit data really quickly over long distances on earth

optical fibres

what are two things ultraviolet light can be used for

give sun tans

destroy microorganisms in water sterilisation

what is fluorescence

ultraviolet light being absorbed and re emitted as visible light energy

what are the two types of lenses

convex

concave

how do concave lenses refract rays

refract parallel rays outwards

how do convex lenses refract rays

refract parallel rays inwards to a single point

how does the focal length affect the power of the lens

the smaller the focal length the more powerful the lens

what does an opaque object not do

transmit light

reguarding temperature what will happen to an object when it absorbs radiation

it will become warmer

what happens to an object when it emits radiation

it will cool down

what is intensity a measure of

the power of radiation in an area per unit

what type of radiation does an object which is mainly at room temperature emitt

infrared

why can sound not travel through a vacuum

because there are no particles in that vacuum for sound waves to vibrate off

why does sound travel fastest in solids and slowest in gases

because in solids the particles are much more densely compacted and there is more meaning the sound waves can quickly vibrate, in gases there is a lack of particles and they’re all spread out meaning sound waves are much slower

how does sound travel in the ear

sound waves make vibrations along the ear canal to the ear drum, then to the ossicles, around the cochlea, and are transmitted into electrical signals to the auditory nerve which then transmits to impulses to the brain

are sound waves longitudinal or transverse

longitudinal

what is the range of human hearing in Hz

20 - 20000 Hz

what are p - waves

longitudinal waves which can travel through solids and liquids

what are s - waves

transverse waves which travel through solids

which wave is faster ; p-waves or s-waves

p-waves

what do seismometers detect

seismic waves

state two uses of ultrasound

for a sonar

pregnancy scans

state two uses pf infrasound

studying earths structure

detecting seismic activity