Chloe CHEUNG - Year 9 Physics Assessment

Transverse Waves

Waves in which the medium moves perpendicular to the direction of wave. (radio waves, microwaves, infared waves, Ultraviolet light, water ripples)

Longitudinal Waves

Waves in which the medium moves parallel to the direction of wave. (sound, spring vibration, earthquake)

Law of reflection

The law of reflection states that when light bounces off a smooth surface, the angle of the incoming light equals the angle of the outgoing light

Elements of Transverse

peak/crest, trough, amplitude, equilibrium position (zero displacement), wavelength

Elements of Longitudinal

wavelength, compression, rarefraction

Low amplitude

Low/High frequency

High amplitude

Low/High frequency

Waves are vibration through…

Oscillation

Amplitude

big or small

Frequency

high or low

Wavelength

long or short

small amplitude

small amplitude, low frequency, long wavelength

small amplitude, high frequency, short wavelength

big amplitude, low frequency, long wavelength

big amplitude, high frequency, short wavelength

wavelength measures (y)

space (metres)

period (T)

time (seconds)

Frequency (f) is

the number of waves per second (Hz).

Period (T) is

the time (sec) it takes for one wave.

higher frequency

(shorter period)

lower frequency

(longer period)

f=

1/T

T=

1/F or time taken/number of waves

mm>/<sec

/1000 ×1000

mHz>/<Hz>/<kHz

/1000 ×1000

Identify the highest frequency you can hear 

20,000 Hz (20 kHz)

Electromagnetic spectrum

• radio waves

• microwaves

• infared waves

• ultraviolet light

• visible light

• x rays

• gamma rays

CONVEX (diverging)

CONCAVE (converging)

converging and diverging irl

spoon, magnifying glass, glasses (near/farsighted), microscopes

WAVE EQUATION wavespeed (v) =

frequency x wavelength

frequency =

speed/wavelength

wavelength =

speed/frequency

highest frequency humans can hear

20,000 Hz (20 kHz)

high frequency

high pitch

low frequency

low pitch

how to describe how waveform sounds

frequency and pitch/amplitude and loudness

how are secondary colours made

by mixing equal amounts of 2 primary colours

EM waves all travel at the same speed through a vacuum, but have different wavelengths, frequencies, energies.

radio waves

bluetooth/wifi

Extremely powerful equipment can heat body tissue too fast and cause deep burns.

microwaves

heat up food

Handling hot dishes or boiling liquids from containers causes a lot injuries.

infared waves

thermal imaging used in strict searches

Excessive heat can lead to heat exhaustion, heat stroke, dizziness and headaches.

visible light

sunlight provide light for human and animal vision

if looked at for too long, the human eye can be blinded

ultraviolet light

uv sterilisation disinfection

if you stay in the sun too much (overexposure), the human body can burn

x ray

internal imaging

small chance of causing cancer due to cell damage

gamma rays

gamma knife, cancer treatement destroys tumors and cancer cells

can destroy dna

why we see different colours

White light contains all colors of the visible spectrum (Red, Orange, Yellow, Green, Blue, Indigo, and Violet). How we see different colors depends entirely on how light waves interact with materials through being absorbed, reflected, or transmitted.

how does sound travel from objects to ear

object makes sound by vibrating > vibrations pass through air by making air molecules vibrate back and forth > vibrations are picked up by ear drums

components of ear

nearsighted

myopia

farsighted

hyperopia

refraction

the bending or redirection of a wave (such as light, sound, or water) as it passes from one medium to another, caused by a change in the wave's speed

refraction rl examples

glasses, camera, microscope, magnifying glass

move to more dense medium

bend towards normal

move to less denser

bends away normal

waves travel faster through

solids > liquids > gases

what happens when you shine light through prism

as white light moves from the air to the denser glass of the prism, it slows down and bends (refract) toward the normal line. White light is made of combining different colours with different wavelengths, meaning each colour travels in a slightly different speed inside the glass. the colours that make up the white light sepereate and disperse into..