Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

advanced higher physics > Quanta > Flashcards

Quanta Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

What is meant by ‘quantum’? (Quanta)

A

The minimum amount of any physical property involved in an interaction.

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

What does Quantum Theory attempt to explain? (Quanta)

A

Phenomena and experimental observations which could not be explained by classical physics.

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

Who was Quantum Theory first proposed by? (Quanta)

A

Max Planck in 1900.

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

What is Quantum theory required to make sense of? (Quanta)

A

A number of experimental observations, such as spectra, which classical physics can’t explain.

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

What is a black body? (Quanta)

A

A surface that absorbs all wavelengths of electromagnetic radiation and is also the best emitter of e.m radiation at any wavelength.

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

What is the continuous spectrum of radiation a black body emits called? (Quanta)

A

Black body radiation

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

What is the ultraviolet catastrophe? (Quanta)

A

When the graph created by Lord Rayleigh and J.H. Jeans’ equations tended to infinity at shorter wavelengths.

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

How did Planck manage to produce a mathematical equation which could correctly predict black body graphs? (Quanta)

A

He made the assumption that the absorption and emission of radiation could only take place in discrete jumps termed quanta.

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

What equation is used to calculate energy in a quanta jump (Quanta)

A

E = nhf

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

When does the photoelectric effect occur? (Quanta)

A

When electromagnetic radiation is directed at a metal surface and ejects electrons from the metal.

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

Sketch a diagram of the photoelectric effect (Quanta)

A

Remember:

  • Metal plate
  • Photons travelling into plate from left
  • Electrons coming out of plate at right
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which equation is used to calculate the energy of a photon? (Quanta)

A

E = hf

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

What is wave-particle duality? (Quanta)

A

The view that electromagnetic radiation acts both like a wave and like a particle simultaneously

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

What is one piece of evidence for waves behaving like particles? (Quanta)

A

The photoelectric effect: particles of light (photons) causing electrons to be ejected from a metal surface.

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

What is one piece of evidence for particles behaving like waves (Quanta)

A

Electron diffraction: An electron beam bombarding thin films of metal producing diffraction rings (concetric circles)

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

What is compton scattering? (Quanta)

A

An experiment performed by Arthur H Compton which he observed the scattering of x-rays from electrons in a carbon target

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

Sketch a diagram for Compton Scattering (Quanta)

A

Remember;

  • Incident x-ray photon travelling into electron
  • Recoil electron moving up outwards from electron
  • Scattered x-ray photon with longer wavelength moving down outwards from electrom
18
Q

What did Compton’s experiment give clear evidence of? (Quanta)

A

Particle-like behaviour by electromagnetic radiation.

19
Q

What is the uncertainty principle in terms of the position and momentum of a quantum particle? (Quanta)

A

It is not possible to measure the position and momentum of a particle simultaneously

20
Q

What is the uncertainty principle in terms of the energy and lifetime of a quantum particle? (Quanta)

A

It is not possible to know the lifetime of a quantum particle and its associated energy charge simultaneously.

21
Q

Why is quantum physics needed to account for quantum tunnelling? (Quanta)

A

•Consider an electron near an energy barrier.

Classical physics - electron will bounce off of barrier unless it has enough energy to ‘leap’ over it

Quantum physics - even if the electron has energy lower than the barrier, there is finite probability that it can ‘tunnel’ through to the other side

22
Q

What is meant by ‘cosmic rays’? (Quanta)

A

Energetic particles from outer space which enter the earth’s atmosphere.

23
Q

What two types of particle make up the majority of all cosmic rays reaching the Earth’s atmosphere? (Quanta)

A

Protons - 89%

Alpha particles- 9%

24
Q

What happens when the cosmic rays strike the top of Earth’s atmosphere? (Quanta)

A

A cosmic air shower is produced

- This is a shower of secondary particles including electrons, photons, neutrinos and muons.

25
Q

Why will charged particles enter the Earth’s magnetic field will follow a helical path? (Quanta)

A

If particles enter the magnetic field at an angle, the two components of a particle’s velocity cause it to foow a helical path

Component perpendicular to the magnetic field creates the circular motion, parallel component creates pitch in helix

26
Q

What is meant by the ‘solar wind’? (Quanta)

A

A stream of charged particles which escale from the upper atmosphere of the sun.

It flows outwards as a plasma at high speed.

27
Q

How does the Earth retain it’s atmosphere despite being exposed to the solar wind? (Quanta)

A

The Earth’s magnetic field helps to retain it’s atmosphere since it deflects the solar wind around the planet.

28
Q

How are the northern and southern lights produced? (Quanta)

A

Cosmic particled trapped in Earth’s magnetic field enter atmosphere neart north and south poles.

Nitrogen, oxygen molecules become excited and emit light when they return to their ground state.

29
Q

What is meant by ‘Simple Harmonic Motion’ (SHM)? (Quanta)

A

The repeated motion of an object under the influence of an unbalanced force (restoring force).

30
Q

Which direction does the restoring force act towards? (Quanta)

A

The equilibrium position, is proportional to the object’s displacement.

31
Q

What is an example of SHM? (Quanta)

A

A mass on a string.

32
Q

What is meant by ‘damping’ in SHM? (Quanta)

A

When an oscillating system loses energy to frictional forces.

The amplitude of the motion decreases to 0 over time.

33
Q

What is the formula for displacement when y=0 and t=0 (Quanta)

A

y = A x (sin) x w x t

34
Q

What is the formula for displacement when y=A and t=0 (Quanta)

A

Y = A cos wt

35
Q

Deprive an expression for velocity (v) (Quanta)

A

Start with v=dy/dt

Differentiate y = Asinwt with respect to t:

V = d/dt x (Asinwt)

V= Awcoswt

since sin^2wt + cos^2wt = 1 then

v = _+_Aw(sqrt)1-sin^2wt

Simplified: v= _+_Aw(sqrt)1- y^2/A^2

v= _+_w(sqrt)A^2 - y^2

36
Q

What is the equation to find maximum velocity when y = 0? (Quanta)

A

Vmax = Aw

37
Q

Deriving an expression for Acceleration (Quanta)

A

a = dv/dt = d^2y/dt^2

Differentiating with respect to t:

a = d/dt x (Awcoswt)

a = -Aw^2 x sinwt

Since y= Asinwt:

a = -w^2 x y

38
Q

What is he equation to find maximum acceleration of an object undergoing SHM (Quanta)

A

amax = w^2 A

39
Q

What is the equation to find Kinetic Energy in SHM (Quanta)

A

Ek = 1/2 mv^2 (A^2 - y^2)

40
Q

What is the equation to find maximum kinetic energy? (Quanta)

A

Ek,max = 1/2 mw^2A^2

41
Q

What is the equation to find potential energy? (Quanta)

A

Ep = 1/2mw^2y^2

advanced higher physics (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions