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Physics ALevel OCR > Waves > Flashcards

Flashcards in Waves Deck (36)
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1
Q

what is a progressive wave

A

a wave that travels through matter (or in some cases a vacuum) and transfers energy from A to B but not matter

2
Q

equation for velocity of a wave

A

v=f(lamda)

3
Q

equation for frequency

A

f=1/T

4
Q

what is intensity proportional to

A

amplitude^2

5
Q

what are coherent waves

A

waves emitted from two sources that have constant phase difference

6
Q

when two waves superpose what happens

A

at points in phase, constructive interference

at points out of phase, destructive interference

7
Q

how are stationary waves created

A

reflected wave superposes
antiphase points create nodes with zero displacement
in phrase points create antinodes with max displacement
distance between node and antinode = half wavelength

8
Q

when two waves interfere to create interference patterns, where are maxima and minima formed?

A

when path difference is an integer multiple of wavelength then a maxima is formed
when path difference in (n+1/2)(lamda) then a minima is formed

9
Q

path and phase difference at central maxima

A

0 and 0

10
Q

path and phase difference at first order minima

A

1/2 lamda and pi

11
Q

path and phase difference at first order maxima

A

lamda and 2pi

12
Q

what is the fundamental frequency

A

the minimum frequency for a standing/stationary wave

13
Q

equation for youngs double slit experiment

A

lamda=ax/D a=slit separation D=distance between slits and board showing interference pattern x=separation between fringes

14
Q

in reflection what angle equals what angle

A

angle of incidence = angle of reflection

15
Q

equation for refractive index

A

n=c/v c=speed of light 3X10^8

v= speed of light through material

16
Q

refraction law equation

A

n1sin(x1)=n2sin(x2)

x=angle between ray and normal

17
Q

what is refraction

A

occurs when a wave changes direction as it changes speed when passing from one medium to another

18
Q

what is diffraction

A

the spreading out of a wave when it passes through a gap or around an obstacle.

19
Q

when does maximum diffraction occur

A

when the gap is the same size as the wavelength of the wave

20
Q

what is polarisation

A

when particles oscillate in one plane/direction

21
Q

what is the intensity of a progressive wave?

A

the radiant power passing through a surface per unit area

22
Q

equation for intensity

A

I=P/A

23
Q

equation for intensity radiated from a sphere

A

I=P/4(pi)r^2

24
Q

order of EM

A

Red midgets interfere very usually xylophone gigs

radio, micro, infra, visible, ultra, xray, gamma

25
Q

in this order how does frequency and wavelength change

A

frequency increases

wavelength decreases

26
Q

wavelength of radio waves

A

10^6 to 10^-1

27
Q

wavelength of microwaves

A

10^-1 to 10^-3

28
Q

wavelength of infrared

A

10^-3 to 700nm

29
Q

wavelength of visible

A

700nm to 400nm

30
Q

wavelength of ultraviolet

A

400nm to 10^-8

31
Q

wavelength of xray

A

10^-8 to 10^-13

32
Q

wavelength of gamma

A

10^-10 to 10^-16

33
Q

equation for frequency of em

A

f=c/lamda

34
Q

conditions for total internal reflection

A

light must be travelling in a medium with a higher refractive index and strike a boundary with a medium of lower refractive index
angle at which it meets boundary must be bigger than the critical angle

35
Q

equation to find critical angle

A

sinc=1/n

36
Q

total internal reflection critical angle with prism

A

sinc=n2/n1