oscilltions and waves

Question 1

time period

Answer 1

the amount of time it takes an oscillating particle to complete one cycle (an oscillation)

Question 2

displacement

Answer 2

the distance of the oscillating object from equilibrium

Question 3

wave

Answer 3

propagation of energy through a material substance

Question 4

refraction

Answer 4

the bending of waves through materials due to a difference in speed

Question 5

amplitude

Answer 5

the maximum displacement from equilibrium an oscillating particle reaches

Question 6

transverse wave

Answer 6

a wave in which the direction of disturbance is perpendicular to the direction of energy transfer

Question 7

longitudinal wave

Answer 7

a wave in which the disturbance is parallel to the direction of energy transfer

Question 8

what is light

Answer 8

an electromagnetic transverse wave

Question 9

reflection

Answer 9

when a wave hits the boundary between two media part of the wave comes back at the same angle

Question 10

what type of wave is sound

Answer 10

longitudinal

Question 11

velocity of a sound wave travelling through air at 20*C and normal atmospheric pressure

Answer 11

340m/s

Question 12

what happens to the speed of sound at higher temperatures?

Answer 12

velocity is greater since the molecules move faster

Question 13

ray

Answer 13

shows the direction of a wave

Question 14

wavefront

Answer 14

line joining points between waves

Question 15

relationship between rays and wavefronts

Answer 15

ray is perpendicular to wavefront

Question 16

if wavelength is shorter, velocity is

Answer 16

decreased

Question 17

how can u tell from a graph that smth’s oscillating?

Answer 17

sign of velocity changes -> direction changes -> body is oscillating

Question 18

what does the area under a velocity time graph show?

Answer 18

the displacement

Question 19

explain why you can only refer to the speed of light rather than velocity

Answer 19

velocity = displacement/time where displacement is the distance moved in a certain direction, however light spreads out in all directions

Question 20

state the principle of superposition

Answer 20

superposition is what happens when two waves coincide: the displacements of waves add vectorially to produce a resultant wave

Question 21

refraction

Answer 21

when a wave hits the boundary between two media part of the wave passes into the new medium with a change of angle

Question 22

diffraction

Answer 22

when a wave passes through a narrow opening it spreads out

Question 23

superposition

Answer 23

when two waves coincide the displacements at a point add

Question 24

wave speed

Answer 24

the distance travelled by the wave profile per unit time

Question 25

nodes

Answer 25

positions where the displacement is always 0, separated by (wavelength/2)

Question 26

antinodes

Answer 26

positions of maximum displacement

Question 27

state the principle of superposition

Answer 27

superposition is what happens when two waves coincide: the displacements of waves add vectorially to produce a resultant wave

Question 28

refraction

Answer 28

when a wave hits the boundary between two media part of the wave passes into the new medium with a change of angle

Question 29

diffraction

Answer 29

when a wave passes through a narrow opening it spreads out

Question 30

superposition

Answer 30

when two waves coincide the displacements at a point add

Question 31

wave speed

Answer 31

the distance travelled by the wave profile per unit time

Question 32

when are standing waves formed in strings?

Answer 32

formed when two waves of the same frequency travel in opposite directions along the same string. Happens when a wave reflects back and forth along a clamped string

Question 33

constructive interference

Answer 33

if waves add when they superpose.

Question 34

graph of displacement against time

Answer 34

sine

Question 35

graph of velocity against time

Answer 35

cosine

Question 36

graph of acceleration against time

Answer 36

sine graph

Question 37

radian definition

Answer 37

arc length/radius

Question 38

why do radians have no units

Answer 38

ratio of two lengths

Question 39

what does narrowing the slit in youngs experiment do

Answer 39

pattern becomes more spread out

Question 40

what are youngs fringes used to measure

Answer 40

the wavelength of light

Question 41

in refraction what changes and what stays the same

Answer 41

wavelength changes but frequency stays the same

Question 42

how and why will youngs fringes change if the filter is switched from red to blue

Answer 42

blue light has a shorter wavelength so the fringes will be closer together

Question 43

in the equation s =wavelengthD/d, what are s, D and d?

Answer 43

``` s = distance between 2 successive fringes D = distance from slits to screen d = distance between slits ```

Question 44

when is velocity of an oscillator maximum?

Answer 44

when the bob passes the equilibrium point

Question 45

what is the intensity of light measured in

Answer 45

Wm^-2

Question 46

what is intensity

Answer 46

energy per area

Question 47

phase difference

Answer 47

the difference between two oscillations that are not in time with each other measured in terms of angle in radians, a difference of pi is completely out of phase

Question 48

a path difference of 1/2wavelength introduces a phase difference of

Answer 48

pi

Question 49

distance between 2 nodes

Answer 49

half wavelength

Question 50

gamma ray wavelength order of magnitude

Answer 50

10^-12

Question 51

x ray wavelength order of magnitude

Answer 51

10^-10

Question 52

what does it mean if numbers differ by one order of magnitude

Answer 52

x is about 10x different in quantity to y

Question 53

ultraviolet wavelength order of magnitude

Answer 53

10^-8

Question 54

visible light wavelength order of magnitude

Answer 54

0.5x10^-6

Question 55

infrared wavelength order of magnitude

Answer 55

10^-5

Question 56

microwave wavelength order of magnitude

Answer 56

10^-2

Question 57

radio wavelength order of magnitude

Answer 57

10^3

Question 58

Incident radiation from Sun calculate

Answer 58

calculated by multiplying the Solar Constant by the cross-sectional surface area of the Earth.

Question 59

calculate Radiation reflected by the Earth

Answer 59

Multiply the radiation incident on the Earth by the albedo of the Earth

Question 60

calculate Radiation emitted by the Earth

Answer 60

Found by using the Stefan-Boltzmann Law (must use the total surface area of the Earth as energy is emitted in all directions). Unless stated otherwise (such as in the example to the left) assume emissivity is 1.

Question 61

order of magnitude surface area of earth in m

Answer 61

10^14

Question 62

sa of earth in m

Answer 62

5.1x10^14

Question 63

how do control rods slow down the reaction

Answer 63

absorbing neutrons, preventing them from being absorbed by 235U, leading to further fissions.

Question 64

why does a pool look shallower than it actually is

Answer 64

light bends as it comes out of the pool (refraction)

Question 65

why is the magnitude of the tension in the string of a pendulum at its midpoint of oscillation greater than the weight of the pendulum bob?

Answer 65

the pendulum bob accelerates towards the centre of the circular path, hence there is a force upwards that adds to the tension produced by the weight

Question 66

what happens if angle of incidence is the critical angle

Answer 66

refracted ray is refracted along the boundary

Question 67

what happens if angle of incidence is greater than critical angle

Answer 67

total internal reflection

Question 68

phase difference between particles standing wave vs progressive wave

Answer 68

All points between two nodes on a standing wave are in phase whereas points on a progressive wave that are closer than one wavelength are all out of phase

Question 69

the total energy of an object undergoing simple harmonic motion is proportional to...?

Answer 69

its mass