waves ✓

Question 1

what are the units for wavelength ?

Answer 1

metres m

Question 2

what are the units for frequency ?

Answer 2

Hertz Hz

Question 3

what are the units for wavespeed ?

Answer 3

metres per second m/s

Question 4

what are the units for period ?

Answer 4

seconds s

Question 5

what are the units for angle ?

Answer 5

degrees

Question 6

what are the units for refractive index ?

Answer 6

there are no units

Question 7

what two things do waves transfer ?

Answer 7

energy and sometimes information

Question 8

what do waves not transfer

Answer 8

matter

Question 9

what are the differences between longitudinal and transverse waves ?

Answer 9

• the movement of the particles on a longitudinal waves are in the same direction as the wave (energy)
• the movement of the particles in a transverse wave is perpendicular to the direction of the wave (energy)

Question 10

what are some names of transverse waves ?

Answer 10

light, UV, gamma, microwave, radio and infer red

Question 11

what uses longitudinal waves ?

Answer 11

sound

Question 12

how can you make different types of waves ?

Answer 12

• use a slinky and push the slinky forward to create a longitudinal waves
• move the slinky from side to side to make a transverse wave

Question 13

what is the wavelength of a wave ?

Answer 13

the distance from one peak to the next

Question 14

what is frequency of a wave ?

Answer 14

how many complete wavers there are per second passing a certain point

Question 15

what is amplitude of a wave ?

Answer 15

the height of the wave from rest to crest/peak of wave

Question 16

what is speed of a wave ?

Answer 16

how fast the wave goes

Question 17

what is period of a wave ?

Answer 17

the time it takes for one complete wave to pass a point

Question 18

what is trough of a wave ?

Answer 18

the lower dip of the wave under the rest position

Question 19

what is peak of a wave ?

Answer 19

the top of the wave above the rest position

Question 20

what is an experiment to measure the speed of sound in air ?

Answer 20

• stand facing towards a building
• measure the distance between you and the building
• hit some Claves together
• start a stop watch at the same time as when you hit Claves together
• stop the stop watch when you hear the echo of the Claves
• use the equation speed = distance X time

Question 21

what is the frequency range for humans ?

Answer 21

20 Hz - 20 000 Hz

Question 22

on an oscilloscope what does a low frequency/low pitch look like ?

Answer 22

waves are further apart from each other

Question 23

on an oscilloscope what does a high frequency/high pitch look like ?

Answer 23

waves are closer together

Question 24

on an oscilloscope what does a low amplitude/ quiet look like ?

Answer 24

small waves

Question 25

on an oscilloscope what does a big amplitude/loud look like ?

Answer 25

tall waves

Question 26

what is the Doppler effect ?

Answer 26

- waves produced by a source moving towards or away have different wavelengths than if they were stationary - wavespeed is constant, if moving it catches up to the waves in front causes the wavefronts to bunch up in front of the moving source and spread out behind it - frequency when coming towards you will seem higher and its wavelength will seem shorter - frequency when moving away will seem lower and its wavelength will seem longer

Question 27

what is the equation for wavespeed ?

Answer 27

wavespeed = frequency x wavelength

Question 28

is visible light part of the electromagnetic spectrum ?

Answer 28

yes

Question 29

what do the colours in visible light correspond to ?

Answer 29

wavelength

Question 30

which colour shows the longest wavelength ?

Answer 30

red (infra red)

Question 31

which colour shows the shortest wavelength ?

Answer 31

blue (ultra violet)

Question 32

what are the 7 parts of the electromagnetic spectrum ? (from longest wavelength to shortest)

Answer 32

``` Radio waves Micro-waves Infra-red Visible light Ultra-violet X-rays Gamma rays ```

Question 33

what is an acronym to learn the parts of the electromagnetic spectrum ?

Answer 33

``` Raging Martians Invaded Venus Using Xray Guns ```

Question 34

which part of the electromagnetic spectrum has the highest frequency ?

Answer 34

Radio waves

Question 35

which part of the electromagnetic spectrum has the lowest frequency ?

Answer 35

Gamma rays

Question 36

what are waves that have a higher frequency ?

Answer 36

more dangerous

Question 37

what speed do all parts of the electromagnetic spectrum travel at in at vacuum ?

Answer 37

the speed of light

Question 38

what are two uses of Radio waves ?

Answer 38

- broadcasting and communication | - television

Question 39

what are two uses of Micro waves ?

Answer 39

- cooking | - mobile phones

Question 40

what are two uses of Infra red waves ?

Answer 40

- heater | - night vision

Question 41

what are two uses of Visible light waves ?

Answer 41

- photography | - communication

Question 42

what are two uses of Ultra violet waves ?

Answer 42

- tanning beds | - security markings

Question 43

what are two uses of X-ray waves ?

Answer 43

- x-rays | - airport security

Question 44

what are two uses of Gamma waves ?

Answer 44

- sterilising medical equipment | - radio therapy

Question 45

what are the dangers of being exposed to micro waves ?

Answer 45

- internal heating of body tissues | - microwaves excite water molecules and cause them to gain kinetic energy

Question 46

what are the dangers of being exposed to infra red waves ?

Answer 46

- causes skin burns

Question 47

what are the dangers of being exposed to ultra violet waves ?

Answer 47

- damage to surface cells and blindness - can damage skin cells - can damage retina causing blindness

Question 48

what are the dangers of being exposed to gamma ray waves ?

Answer 48

- causes cell mutation | - can cause cancer

Question 49

what can happen to all waves ?

Answer 49

they can be reflected, refracted and diffracted

Question 50

what is the law of reflection ?

Answer 50

angle of incidence = angle of reflection

Question 51

what is an experiment to investigate the refraction of light in a prism ?

Answer 51

- shine light in triangular prism - different wavelengths of light refract by different amounts - white light disperses into different colours as it enters the prism - similar effect when light leaves the prism - get a rainbow effects from light as it leaves

Question 52

what is the equation for refractive index ?

Answer 52

refractive index = sin (incidence) ÷ sin (refractive)

Question 53

how do you measure the refractive index of glass ?

Answer 53

- put a light box in front of the glass block - draw the normal - plot points of the light going into the block and out of the glass block - measure the angle of incidence - measure the angle of reflection

Question 54

how can the refractive index of a glass block experiment be improved ?

Answer 54

- take readings at different angles - plot a graph of sin (i) against sin (r) - measuring the gradient of a linear line of best fit to determine the refractive index

Question 55

how is total internal reflection used to send information along optical fibres ?

Answer 55

- optical fibres are made of plastic or glass - have a central core surrounded by cladding with a lower refractive index - core of the fibre is narrow - light signals passing through always hit the core cladding boundaries at angles higher than the critical angle - light is always totally internally reflected

Question 56

what is the significance of the critical angle (c) ?

Answer 56

- it is the minimum angle at which total internal refraction occurs - any angle greater than the critical angle, total internal reflection occurs and the light ray obeys the normal rules for reflection

Question 57

what is the equation to show the relationship between the critical angle and refractive index ?

Answer 57

sin (c) = 1 ÷ n c = critical angle n = refractive index