Waves -Terms and definitions

Question 1

Energy Transfer

Answer 1

Wave motion, in general, is a process in which kinetic energy is transferred from one point to another without any transfer of matter between the points

Question 2

Mechanical waves

Answer 2

requires a material medium

eg. sound waves

Question 3

Electromagnetic waves

Answer 3

do not require a medium (can travel in vacuum)

eg. light

Question 4

Longitudinal waves

Answer 4

vibrate parallel to the direction of motion

eg. sound waves

Question 5

Transverse waves

Answer 5

vibrate perpendicular to the direction of motion

eg. light, water

Question 6

Amplitude (A)

Answer 6

the maximum distance a particle is displaced from its rest position

Question 7

Wavelength (λ)

Answer 7

The distance between two successive corresponding positions in a wave (m)

Question 8

Wave velocity (v)

Answer 8

the velocity of the wave shape

Question 9

Frequency (f)

Answer 9

Number of waves to pass a point in a second

Hertz (Hz)

Question 10

Period (T)

Answer 10

The time (s) it takes for one wave to pass a point
Seconds (s)

Question 11

T=1/f

Answer 11

T = Period (s)
f = frequency (Hz)

Question 12

f=1/T

Answer 12

f = frequency (Hz)
T = Period (s)

Question 13

v=fλ

Answer 13

v = velocity (m/s)
f = frequency (Hz)
λ = wavelength (m)

Question 14

Pulse in Heavy String

Answer 14

Travels slowly

Question 15

Pulse in Light String

Answer 15

Travels quickly

Question 16

Deepwater -> shallow water (refraction)

Answer 16

Waves slow down
wavelength increases
bends behind

Question 17

shallow water -> deep water (refraction)

Answer 17

Wave speeds up
wavelength decreases
bends forwards

Question 18

Refraction

Answer 18

change in speed when a wave travels from one medium into another
frequency (f) does not change
Speed (v) changes
wavelength (λ) changes

less optically dense medium -> more optically dense
slows down
bends towards the normal

Question 19

Superposition

Answer 19

Ability for waves to superimpose (add their displacements and their energy) as they move through each other

Question 20

Interference

Answer 20

pattern of waves produced by two source points

Question 21

Principle of superposition

Answer 21

two waves to be ‘added’ together by adding their displacements together at each instant in time

Question 22

Constructive interference

Answer 22

crest meets crest or

trough meets trough

Question 23

Total Internal Reflection

Answer 23

Angle of incidence is greater than the critical angle, all the light reaching the boundary is reflected.
Criteria:
1. Must go from optically dense -> less dense
2. 0i must be greater than critical angle

Question 24

Nodal lines

Answer 24

(flat)
destructive interference
amplitude = 0
wave arrive 180° out of phase

Question 25

antinodal lines

Answer 25

(Large height) constructive interference maximum amplitude wave arrive 180° in phase

Question 26

Path Difference | PS1-PS2 = (n-(1/2)λ

Answer 26

PS1 = PS2 = n = λ =

Question 27

Path Difference | PS1-PS2 = nλ

Answer 27

PS1 = PS2 = n = λ =

Question 28

Speed of light

Answer 28

3.00x10^8 m/s

Question 29

Laws of Reflection

Answer 29

Incident ray, reflected ray, normal line all lie in the same plane the angle of incidence is equal to the angle of reflection

Question 30

1/f = 1/di + 1/do

Answer 30

``` f = focal length di = distance of image do = distance of object ``` NOTE: f is negative when convex mirror di is negative when virtual image

Question 31

m = hi/ho = di/do

Answer 31

``` m = magnification hi = image height ho = object height di = image distance do = object distance ``` NOTE: f is negative when convex mirror di is negative when virtual image

Question 32

Critical Angle

Answer 32

angle of refraction is 90° to the angle of incidence

Question 33

Refractive index

Answer 33

``` n = sin01/sin02 01 = incident angle 02 = refraction angle n = optic density/refractive index ```

Question 34

Snell's law λ1/λ2 = v1/v2 = sin01/sin02 = n2/n1 n1sin01 = n2sin02

Answer 34

``` λ = wavelength (m) v = velocity (m/s) 01 = incident ray 02 = refractive ray n2 = refractive index of medium 1 n1 = refractive index of medium 1 ```

Question 35

Dispersion

Answer 35

different frequencies of light splitting up through a prism red has longest λ so bends the least violet has shortest λ so bends the most

Question 36

Concave mirror within focal length

Answer 36

Virtual Enlarged Upright