waves- sound and light

Question 1

What are the 4 types of waves?

Answer 1

transverse, longitudinal, mechanical and electromagnetic

Question 2

what are the characteristics of a transverse waves? Give an example

Answer 2

the resting point- is the balance point of the wave if there was no wave it would be on the resting point
crest- the top of the wave
trough- the bottom of the wave
EG. LIGHT

Question 3

what are the characteristics of a longitunal wave? Give an example

Answer 3

compression- a region of a wave where the particles are closest together
rarefraction a region of the wave where particles are fartest apart
EG. SOUND

Question 4

what is a wavelength?

Answer 4

a wavelength is a measurement of the size of the wave
tranverse is measure from crest to crest
longitundal is measure from compression ot comression
MEASURED IN CM

Question 5

what are the movements of a transverse wave?

Answer 5

the 2 movements are perpendicular the wave moves up and down and towards and away from the sorce of the sound

Question 6

what are the movement of a longitudinal wave

Answer 6

the 2cmovements are parallela longitundal wave is like a spring the coils move back and forth and the force pushing the spring also moves back and forth

Question 7

what is a mechanical wave?

Answer 7

is a wave that needs a meduim (a subtance through which a wave travels EG. SOLID LIQUID GASES) to go through
EG. SOUND

Question 8

what is an eltromagnetic wave?

Answer 8

is a wave that does not need a meduim to travel through
EG. LIGHT

Question 9

What is amplitude?

Answer 9

amplitude is the maxium displacement from the restiong point the mesurement between the resting point and the crest
MEASURED IN CM

Question 10

what is frequency

Answer 10

Is the number of waves passing a point in some time interval
UNIT IF MEASUREMENT HERTZ
1HZ=1 wave\sec

Question 11

how does elasticity affect the speed of a wave

Answer 11

elasacity is how easily a wave bounces on a meduim the particles in a meduim the more elastic it is
SOLID>LIQUID>GASES

Question 12

hiow does denstiy affect the speed of a wave

Answer 12

waves travel faster in less dense meduims beacise there are less particles to travel through

Question 13

how does tempature afftect the speed of a wave

Answer 13

with more heat particles waves move faster and there is more enegy so waves travel faster in hotter places

Question 14

how to calculate speed of sound

Answer 14

speed (m\s)= distance(m) ÷ time (sec)
speed with wave = wavelength x frequency
speed of sound= 300 m\s
speed of light= 300 million m\s

Question 15

what is wave interfence?

Answer 15

wave interference is the when 2 or more waves interfer
interfence is the reacation to the 2 waves meeting

Question 16

what is deconstructive interfernce

Answer 16

is when 2 waves meet and they have the same frequency but are out of phaseso they cancel eachother out

Question 17

what is constructive interference

Answer 17

is when 2 waves meet they have the same frequency and are in phase so they add to make a bigger wave

Question 18

what are beats?

Answer 18

deconstructive and constuctuive are the 2 extreme exaples
most waves are different so it will form a note with varialble amplitude this is heard in the ear as beats

Question 19

how does sound enter the ear

Answer 19

the sound wave enters the war goes through the ear canal and hits the ear drum which vibrates
this sets the osticular chain in motion 3 bones that vibrate and the sound wave then travels to the inner ear where it enters the cochlea

Question 20

how does the brain understand sound

Answer 20

in the cochlea the sound wave is changed in to complex elctrical signals that which are passed to the nerves that travel to the brain
the cochlea is a sprialed shaled thing filled with fluid. it has tiny hair cells that have varying sensetivity for the brain to understand the different frequecies and tones

Question 21

what types of waves are light

Answer 21

transverse and eletrcomagnetic

Question 22

what was issac newtons theory of light

Answer 22

the property of a wave is that it can bend but you cant see light around a corner so its not a wave

Question 23

what is diffraction

Answer 23

diffraction is the divation of light

Question 24

wht is rafraction

Answer 24

is the bending of a wave as it moves through meduims at an angle
eg. coin in water- light reflects and travels toward the observer
as light moves form water to air it speeds up and bends
thebrain does not believe light bends and makes a virtual image straight ahead

Question 25

what is electromagnetic radiation

Answer 25

electronagntic radition is the energy that is transferred by electromagnetic waves

Question 26

what are the 2 types of lenses

Answer 26

convex or convering lense meaning when light passes through and when refracted the waves meet at a focal point eg. OUR EYES concave or diverging lense has an indent curve so when light waves pass through

Question 27

what are the properties of a convex lense (how light travels through)

Answer 27

the light enters through its a curved surface so light bends the thickness of the lense will effect when the light waves meet it is called a focal point and the length between the focal point and the lense is called the focal legth

Question 28

how can images be formed by a lens (charateristics)

Answer 28

it can be bigger or smaller or the same size inverted or right way up closer of farther real or virtual - when refracted rays meet on the same side of the lense its virtual

Question 29

how are virtual images formed in the lenses

Answer 29

concave- always forms a virtual image because the light never meets so the brain fills in and makes a focal point where the 2 rays seem to be meeting convex- only makes a virtual image when the oblect is in between the focal point and the lense

Question 30

what happens in an incandescent light bulb

Answer 30

electrons move through a copper wire with very low resistence then it transfers to a tungsten filiment with a lot of resistence which mean it conducts frition which meatd heat which = light

Question 31

what happens in a florscent light

Answer 31

electrons travel in the light bulb and smash in to the gas atoms in the light bulb. when they smash in to each other the electrons jump to a higher energy level this is unstable because the light is uv. there is a layer on the light bulb that diffracts some of the energy and light to make it visible again different gases give different coloured light

Question 32

what experiment questioned whether light was a wave or particles

Answer 32

the thomas young 2 slit experiment showed that light was made out of waves

Question 33

explain the 2 slit experiment

Answer 33

2 waves are created by the light going through the slits. on the screen there is a pattern of light and dark strips from the constructive and desctructive interfernce of the waves canceling and adding togther making apattern this disproves newtons theory showing that light travels in a wave

Question 34

what is the photoelectric effeft

Answer 34

einsten did this expirment to see whether light was a wave or particles he shone light on a metal and connected the metal plate to an ammeter. he saw that light dectects current (obvious) he shone blue light and it still detected a current (obvious has a shorter wave length) but when red light was shone there was no current.

Question 35

what did Einsten conclude with the photoelectric effect

Answer 35

einsten said that waves are continous so if you shone red light longer it would eventually form a current but it didnt so light is seperate partices

Question 36

what is polarization

Answer 36

light waves usually travel in all directions but some light waves perfer to go in a certain direction that is called polarized light EG. PHONE ONLY TRAVELS UP AND DOWN there is such thng as a polarized filter which changes light that goes in all dorections to only one