Waves

Question 1

what is a progressive wave

Answer 1

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

Question 2

equation for velocity of a wave

Answer 2

v=f(lamda)

Question 3

equation for frequency

Answer 3

f=1/T

Question 4

what is intensity proportional to

Answer 4

amplitude^2

Question 5

what are coherent waves

Answer 5

waves emitted from two sources that have constant phase difference

Question 6

when two waves superpose what happens

Answer 6

at points in phase, constructive interference

at points out of phase, destructive interference

Question 7

how are stationary waves created

Answer 7

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

Question 8

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

Answer 8

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

Question 9

path and phase difference at central maxima

Answer 9

0 and 0

Question 10

path and phase difference at first order minima

Answer 10

1/2 lamda and pi

Question 11

path and phase difference at first order maxima

Answer 11

lamda and 2pi

Question 12

what is the fundamental frequency

Answer 12

the minimum frequency for a standing/stationary wave

Question 13

equation for youngs double slit experiment

Answer 13

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

Question 14

in reflection what angle equals what angle

Answer 14

angle of incidence = angle of reflection

Question 15

equation for refractive index

Answer 15

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

v= speed of light through material

Question 16

refraction law equation

Answer 16

n1sin(x1)=n2sin(x2)

x=angle between ray and normal

Question 17

what is refraction

Answer 17

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

Question 18

what is diffraction

Answer 18

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

Question 19

when does maximum diffraction occur

Answer 19

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

Question 20

what is polarisation

Answer 20

when particles oscillate in one plane/direction

Question 21

what is the intensity of a progressive wave?

Answer 21

the radiant power passing through a surface per unit area

Question 22

equation for intensity

Answer 22

I=P/A

Question 23

equation for intensity radiated from a sphere

Answer 23

I=P/4(pi)r^2

Question 24

order of EM

Answer 24

Red midgets interfere very usually xylophone gigs

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

Question 25

in this order how does frequency and wavelength change

Answer 25

frequency increases

wavelength decreases

Question 26

wavelength of radio waves

Answer 26

10^6 to 10^-1

Question 27

wavelength of microwaves

Answer 27

10^-1 to 10^-3

Question 28

wavelength of infrared

Answer 28

10^-3 to 700nm

Question 29

wavelength of visible

Answer 29

700nm to 400nm

Question 30

wavelength of ultraviolet

Answer 30

400nm to 10^-8

Question 31

wavelength of xray

Answer 31

10^-8 to 10^-13

Question 32

wavelength of gamma

Answer 32

10^-10 to 10^-16

Question 33

equation for frequency of em

Answer 33

f=c/lamda

Question 34

conditions for total internal reflection

Answer 34

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

Question 35

equation to find critical angle

Answer 35

sinc=1/n

Question 36

total internal reflection critical angle with prism

Answer 36

sinc=n2/n1