physics > ch28 - quantum physics > Flashcards

ch28 - quantum physics Flashcards

(74 cards)

Study These Flashcards
1
Q

particles are objects that are

A

. hard
. have mass
. move around according to Newtonian mechanics laws

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

particles are macroscopic or microscopic

A

macroscopic model

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

kinetic model of gas shows gas particles as

A

. small
. hard particles
. rushing around
. bouncing off container walls

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

for electricity, what is the model and macroscopic phenomenon

A

. model, elctron flow
. phenomenon, current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

for gases, what is the model and macroscopic phenomenon

A

. model, kinetic theory
. phenomenon, pressure and temperature and gas volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

for solids, what is the model and macroscopic phenomenon

A

. model, crystalline materials
. phenomenon, mechanical properties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

for radioactivity, what is the model and macroscopic phenomenon

A

. model, nuclear model of atom
. phenomenon, radioactive decay along with fission and fusion reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

for chemistry, what is the model and macroscopic phenomenon

A

. model, atomic structure
. phenomenon, chemical reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

wave model ideal shape

A

sinusoidal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

in sound wave, varying quantity is

A

pressure or density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

in em wave, varying quantity is

A

electric field strength and magnetic flux density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

in waves on strings, varying quantity is

A

displacement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

characteristic properties of waves

A

show
. reflection (particle model explains)
. refraction (particle model explains)
. diffraction
. interference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

waves themselves do not show

A

. mass
. charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

defining characteristics of waves

A

. diffraction
. interference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

diffraction

A

the spreading of a wave when it passes through a gap or past the edge of an object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

interference

A

the formation of points of cancellation and reinforcement where twk coherent waves pass through each other or the superposition of two or more waves from coherent forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how to see particulate nature of light

A

Geiger counter next to gamma radiation will detect gamma rays but having discrete click (different to alpha/beta one) , which are an em wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

photoelectric effect

A

an interaction between a photon and an electron in a metal, in which the electron is removed from the surface of the metal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

photons

A

a quantum of electromagnetic radiation, a ‘packet of energy’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

E = hf = hc/lambda

A

. E is energy of photon
. h is Planks constant
. f is frequency
. lamda is wavelength
. c is speed of light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Plank constant

A

a fundamental constant that links the energy of a photon E and its frequency

E = hf

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Plank constant value

A
  1. 63 * 10^-34 Js
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
E and f relation
directly proportional
26
Einstein relation
E = hf E = hc/lambda
27
em spectrum in increasing wavelength
. gamma rays . x rays . uv . visible light . infrared . microwaves . radiowaves
28
electronvolt (eV)
the energy gained by an electron travelling through a potential difference of 1V. 1eV = 1.6 * 10^-19 J
29
eV to J
multiply 1.6 * 10^-19
30
J to eV
divide 1.6 * 10^-19
31
threshold voltage
the minimum forward bias potential difference across a light emitting diode (LED) when it starts to conduct and emit light
32
LEDs of different colour light require
different threshold voltages
33
red LED
. emits low energy photons . requires low threshold voltage
34
blue LED
. emits high energy photons . requires high threshold voltage
35
greek word for light
photo
36
experiment to observe photoelectric effect
. clean zinc plate on gold leaf electroscope . if electroscope has negative charge leaf deflects . charging electroscope gives it excess electrons . uv radiation from mercury lamp allows electrons to escape from surface . with uv raditation, leaf will fall . closer the uv radiation, faster the leaf falls uv light REQUIRED
37
threshold frequency
the minimum frequency of the incident electromagnetic radiation that would eject electrons from the surafe of a metal
38
threshold wavelength
the longest wavelength of the incident electromagnetic radiation that would eject electrons from the surface of a metal
39
why do electrons break free from metal with uv light
. there are free electrons in metals . photons of em radiation strike metal . some electrons break free is they have enough energy . one photon for one electron . photon needs more or same as the work function energy of the metal
40
work function energy
the minimum energy required by an electron to free itself from the surface of a metal it is a PROPERTY OF THE METAL symbol is phi
41
photoelectric effect rules
. electrons from surface are removed . one photon can exchange energy with one electron only . surface electron is removed instantaneously when energy of incident photon is greater than or equal to phi (work function of metal) . energy conserved in photon electron interaction . intensity of radiation directly proportional to rate of photon arrival
42
Einstein's photoelectric equation
energy of photon = work function + max ke of electron hf = phi + 0.5mvmax²
43
hf = phi + 0.5mvmax² understanding
. photon has energy hf . energy absorbed by electron . some energy used to escape from metal (phi) . rest energy is ke of electron
44
if incident radiation frequency is same as threshold frequency of metal for photoelectric effect
h fo = phi fo = threshold frequency = phi/ h . lambda o = threshold wavelength = hc / phi
45
if incident radiation frequency is less than threshold frequency of metal for photoelectric effect
. electron absorbs energy as kinetic energy . electron cannot escape positive ion attractive forces . electron loses the ke to metal ions through collision . metal warms up
46
does threshold frequency change according to metal
yes
47
intensity of em radiation is
rate of photons incident to metal surface
48
frequency/ wavelngth of em radiation decides
energy of photon
49
more intensity of em radiation means faster rate of electrons lost?
yes
50
photons have momentum
51
momentum p of photon
p = E/c
52
pressure exerted by photon beam on object
. p, momentum = E/c . number photons per secs = power/energy of each photon . force = no. photons each second * momentum of each photon . pressure = F/A
53
dispersion
the splitting of light into its component wavelengths
54
continuous spectrum
an emission spectrum that consists of a continuum of wavelength
55
methods of light dispersion
. prism . diffraction grating
56
wavelength range, violet to red
400nm to 700nm
57
when is a line spectrum seen
. narrow source . viewed through diffraction grating
58
what can we deduce from line spectra
. certain elements . different gases allow only certain present colours
59
emission line spectra
a spectrum with bright coloured lines of unique wavelengths
60
absorption line spectra
a spectrum with dark lines of a unique wavelength seen against the background of a continuous spectrum
61
energy levels/states
a quantised energy state of an electron in an atom
62
energy levels are
NEGATIVE because external energy is supplied to remove an electron from the atom
63
quantised
a quantity is said to be quantised when it has a definite minimum magnitude and always comes in multiples of that magnitude restricting a variable, observable quantity to discrete values
64
transition
term used to describe a jump made by an electron between two energy levels
65
atoms of different elements have different line spectra
they have different spacing between their energy levels
66
ground state
the lowest energy state that can be occupied by an electron in an atom
67
the energy of a photon, absorbed or emitted is a result of
a transition between two energy levels hf = E1 - E2 hc/lambda = E1 - E2
68
how does light show wave particle duality
. particle: photon, evidence is photoelectric effect . wave: evidence is diffrection and interference of light using slits
69
do all em wave have dual nature
yes
70
de Broglie wavelength
the wavelength associated with a moving particle, given by equation lambda = h/p = h/mv like elctrons moving through space
71
electron diffraction tube experiment
. electrons from a heated filament accelerated at high speeds . acceleration due to large pd between cathode and anode . beam passes through polycrystalline graphite (whicb has large numbers of carbon atoms in uniform layers) . electrons emerge from graphite film . diffraction rings produced on phosphor screen WAVE BEHAVIOUR
72
electron diffraction tube formulae
. lambda = 2d sin0 . 0.5mv² = eV
73
wave particle duality of electron
. particle: evidence from Newtonian mechanics . wave: evidence from electron diffraction
74
two key equations for a photon
. p = E/c . E = hc/ lambda
physics
flashcards
Decks in class (30)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions