physics - waves

?
complete this sentence:
waves transfer _______ and _______ without transferring _______.
waves transfer energy and information without transferring matter
1 of 45
define frequency and give its units
- the number of waves passing through a point per second
- Hz (hertz)
2 of 45
define wavelength
the distance between adjacent peaks on a wave
3 of 45
define amplitude
- the maximum displacement of the wave from its equilibrium position
- the distance between the center of the wave and a peak
4 of 45
what is meant by the period of the wave?
the length of time it takes for one full wave to pass through a point
5 of 45
how do calculate the wave speed?
- wave speed (measured in meters per second) is equal to the product of wavelength and the frequency of the wave

- wave velocity = f x /\
6 of 45
state an equation linking frequency and period of a wave
frequency (Hz) = 1 / period(s)

f = 1
-----
T
7 of 45
what is a longitudinal wave?
give some examples
- vibrations are parallel to the direction of energy transfer (wave)
- examples: sound waves and earthquakes (seismic waves)
8 of 45
what is a transverse wave?
give some examples
- a wave with oscillations that are perpendicular (90 degrees) to the direction of energy transfer
- examples: electromagnetic waves
9 of 45
explain what is meant by 'the Doppler effect'?
when a wave source is moving towards the observer, observed frequency increases and observed wavelength decreases; when a wave source is moving away from the observer, observed frequency decreases and observed wavelength decreases since v = f x
10 of 45
at what speed does an electromagnetic wave travel in a vacuum?
3x10^8 m/s
11 of 45
what type of waves are electromagnetic waves?
transverse
12 of 45
what do electromagnetic waves transfer?
energy and information
13 of 45
what are the four common properties of all electromagnetic waves?
- they are all transverse waves
- they all transfer energy or information
- they all travel at the speed of light in vacuum
- they all can be reflected, refracted or diffracted
14 of 45
which part of the electromagnetic spectrum has the longest wavelength?
radio waves
15 of 45
order the electromagnetic spectrum from the highest frequency to the lowest frequency
1. gamma rays
2. x-rays
3. ultraviolet
4. visible light
5. infrared
6. microwaves
7. radio waves
16 of 45
what is the colors of the visible light spectrum?
red, orange, yellow, green, blue, violet
17 of 45
1. which color has the highest frequency
2. which color has the lowest frequency
3. which color has the lowest wavelength
4. which color has the highest wavelength
1. violet
2. red
3. violet
4. red
18 of 45
what are the uses of radio waves?
- for communication through radio
- used for satellite transmissions
19 of 45
what are microwaves used for?
- cooking in microwaves ovens
- communications
- satellites
20 of 45
which part of the electromagnetic spectrum is used in cooking, thermal imaging and television remote controls?
infrared
21 of 45
give examples of uses for visible light
- allows us to se (used for vision)
- photography
- optical fibres (endoscope, communication)
22 of 45
what part of the electromagnetic spectrum is used for security marking and in fluorescent lamps?
ultraviolet
23 of 45
what are some uses of x-rays?
- scanners at airports
- medical x-ray machines
24 of 45
what are the uses and disadvantages of gamma rays?
- used to sterilize food and medical equipment
- used in cancer diagnosis
- can cause mutations or damage to body cells. this could lead to death
25 of 45
what are the disadvantages of microwaves?
they can cause heating of internal tissues in the body
26 of 45
which part of the electromagnetic spectrum is used in TV remotes and can also cause skin burns?
infrared
27 of 45
does the danger that is associated with electromagnetic waves increase with frequency or with wavelength?
with frequency
28 of 45
what are the dangers of excessive exposure to ultraviolet?
you could damage your eyes and the cells on the surface of your skin. this could lead to skin cancer or eye conditions
29 of 45
what is the normal (in terms of reflection and refraction)?
a vertical imaginary line which is perpendicular to the boundary
30 of 45
what happens when light is reflected off a boundary?
it is reflected (bounces) off a smooth flat surface so that the angle of incidence (the angle it comes in at) is the same as the angle of refraction (the angle it leaves at)
31 of 45
what happens when light is refracted while passing through 2 different medias?
- the light changes speed and direction in the new medium
- if the new medium is more dense, the light will travel slower and bend towards the normal
- if the new medium is less dense, the light will travel faster and bend away from the normal
32 of 45
state an equation linking angle of incidence, angle of refraction and refractive index
n = sin(i)
-----
sin(r)

n = refractive index
i = angle of incidence
r = angle of refraction
33 of 45
what is the critical angle?
the angle of incidence which causes the angle of reflection to be 90 degrees so that the light refracts onto the boundary
34 of 45
state an equation linking critical angle and refractive index
n = 1
-----
sin(c)

n = refractive index
c = critical angle
35 of 45
what is total internal reflection?
when light is trying to pass from a less dense medium to a denser medium, it can be reflected back to the less dense medium if the angle of incidence is larger than the critical angle between two media.

this reflection is called total internal reflectio
36 of 45
state two uses of total internal reflection
- endoscopes
- periscopes
- optical fibres
- cat eye reflectors
- shining of diamonds
37 of 45
if light hits a boundary at 90 degrees to the surface, will the light refract
no it will not
38 of 45
what is the type of sound waves?
longitudinal
39 of 45
what is the range of frequencies that humans can heat (audible range)?
between 20 - 20000 Hz
40 of 45
how would you measure the velocity of sound in air
- echo clap method
- make a sound and record how long it takes to hear it over a large distance
- using two microphones and a data logger
41 of 45
how does sonar work?
when ultrasound waves are emitted they reflect off boundaries and their echoes are detected. the speed of the ultrasound is known and also the time it takes to detect the echoes. the equation distance = speed x time is used to find the distance between th
42 of 45
how does ultrasound scanning work?
an ultrasound wave is sent into the patients body. it passes through the body and reflects off the organs and tissue. the device then uses the reflected ultrasound waves to produce an image of the fetus. ultrasound is safe and therefore does not damage ce
43 of 45
which property of sound waves describes the loudness of the sound?
amplitude (higher amplitude = louder sound)
44 of 45
which property of sound waves describe the pitch of the sound?
frequency (higher frequency = higher pitch)
45 of 45

Other cards in this set

Card 2

Front

- the number of waves passing through a point per second
- Hz (hertz)

Back

define frequency and give its units

Card 3

Front

the distance between adjacent peaks on a wave

Back

Preview of the back of card 3

Card 4

Front

- the maximum displacement of the wave from its equilibrium position
- the distance between the center of the wave and a peak

Back

Preview of the back of card 4

Card 5

Front

the length of time it takes for one full wave to pass through a point

Back

Preview of the back of card 5
View more cards

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