WAVES #2

Question 1

OPAQUE objects do not…

Answer 1

transmit light

Question 2

transparent and translucent objects ….

Answer 2

do transmit light

Question 3

why does a white object appear white`

Answer 3

reflects all of the white light

Question 4

what does white light consist of

Answer 4

ROYGBIV

Question 5

WHY di black objects appear black

Answer 5

they absorb all of the colours in the visible light

Question 6

why do objects appear a colour eg red

Answer 6

a object appears red because it has absorbs all the colours of light except red which it is reflecting

Question 7

what do colour filters do

Answer 7

colour filters filter out different wavelengths of light so that only certain colours are transmitted- the rest are absorbed

Question 8

what would you see if you looked at a red object through a blue filter

Answer 8

the object would look black

Question 9

a student looks at a red bag with a green buckle through a colour green filte. describe whay the student will see

Answer 9

the red bag is reflecting red light and the green buckle is reflecting green light
as it is a green filter only green light will be able to pass through
this means the buckle will appear green as the light reflected can pass through
howeber the bag will appear black because the filter doesn’t allow through the red light being reflected by thr bag

Question 10

every object emits and absorb

Answer 10

infrared radiation

Question 11

the hotter the object the more

Answer 11

infrared radiation it emits

Question 12

an object that is hotter than its surroundings emits more Infrared radiation than it

Answer 12

absorbs. WHICH COOLS IT DOWN

Question 13

an object that is COLDER than its surroundings emits LESS Infrared radiation than it

Answer 13

emits. which warms it up

Question 14

objects at a constant temperature emits

Answer 14

infrared radiation at the same rate theyre absorbing it

Question 15

what are sound waves caused by

Answer 15

vibrating objects

Question 16

explain in terms of vibrations what happens when a sound enters your ear

Answer 16

air particles move back and forth creating pressure on your ear drum
this change in pressure causes the ear drum to vibrate
these vibrations pass from your ear drum to the inside of your ear
these vibrations are turned into electrical signals which ae sent to your brain so you can hear the sound

Question 17

what are echoes

Answer 17

reflected sound waves

Question 18

how is a sound wave created in a speakee

Answer 18

the paper diaphragm in a speaer vibrates back and forth
which causes the surrounding air to vibrate creating compressions and rarefactions
this creates a sond wave

Question 19

why cant sound travel in space

Answer 19

because it mostly a vacuum which means there no available particles to vibrate

Question 20

what is ultrasound

Answer 20

ultrasound is sound with frequencies higher than 20,000hz

Question 21

what is infrasound

Answer 21

anything below 20hz- unable for us to detect

Question 22

what is the speed of sound in air

Answer 22

330m/s

Question 23

what is the speed of sound in water

Answer 23

1500m/s

Question 24

equation when working out ultrasound

Answer 24

speed=distance/time (divided by 2)

Question 25

what do you always have to remember for ultrasound calculations

Answer 25

to divide by two

Question 26

what happens when ultrasound hits a boundary

Answer 26

the ultrasound wave gets partially reflected

Question 27

pre natal scanning

Answer 27

in order to see unborn babies an ultrasound wave with a frequency between 2 and 10 MHz is made an transmitted into the mother the wave is partially refleted when it meets a boundary between two different media these refelctions are collected and interpreted as a picture

Question 28

adv of untrasound scans

Answer 28

non invasive accurate non ionising image is available immediately

Question 29

dis of ultrasound scans

Answer 29

images deeper in the body results in progressively poorer resolution

Question 30

using ultrasou[nd to treat kidnet stones

Answer 30

a high powered ultrasound wwave is used | stones vibrae until the break apart and easily passed out of the body via the the ureatha

Question 31

the diagram shows how ultransonic waves can bee used to clean a watch suggest how

Answer 31

the oscillator vibrates causoing the fluid to knock the dirt off the watch

Question 32

state two features of ultrasound

Answer 32

very high frequency waves | higher frequency than human hearing range

Question 33

diagram shows an ultrasound transmitter the block has an internal crack explain why pulse a and b occur

Answer 33

when the ultrasound goes through the block it sends out three reflections when it enters, when it hits the crack and when it leaves, this is because it has been partially reflected back as it has hit a different boundary pulse a occurred because it has changed density so it has sent a reflection back

Question 34

what are the two types of seismic waves

Answer 34

p waves and s waves

Question 35

what are p waves

Answer 35

``` p waves are longitudinal they travel through solids and liquids they travel faster than s waves can travel through the earth core they are bent by changing the density of the rock ```

Question 36

what are s waves

Answer 36

s waves are transverse they only travel through solids theyre slower than p waves they are bent by changing the density of the rock

Question 37

what are the two types of surface waves

Answer 37

love wave | Rayleigh wave

Question 38

where do the surface waves only travel

Answer 38

in the earths crust

Question 39

what is a black body

Answer 39

is an object that absorbs all of the radiation that hits it, no radiation is reflected or transmitted

Question 40

as the temp of an object increases the intensity

Answer 40

of every emitted wavelength increases

Question 41

the hotter an object is the shorter its

Answer 41

peak wavelength

Question 42

the peak wavelength of the sun is 500nm the peak wavelength of another star is 850nm which star is hotter

Answer 42

the sun is hotter because the hotter an object is the shorter its peak wavelength

Question 43

can pwaves travel through the earths core

Answer 43

yes

Question 44

csn s waves travel through the outer core

Answer 44

no