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EM Radiation and Quantum Phenomena > EM Radiation and Quantum Phenomena > Flashcards

EM Radiation and Quantum Phenomena Flashcards

1
Q

What is a piece of evidence of wave-like properties of electrons?

A

The diffraction of electrons by a metal crystal

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2
Q

What is the equation linking photon energy, Planck’s constant, frequency?

A

Photon energy = Planck’s constant X Frequency

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3
Q

What is needed to remove photoelectrons?

A

A minimum energy of a photon

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4
Q

What does the number of photoelectrons released depend on?

A

Number of photons per second

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5
Q

When an electron collides with an isolated atom, what happens to the colliding electron?

A

It transfers energy to the atomic electron

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6
Q

How is wave property shown?

A

Diffraction or interference

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7
Q

What equation links Photon energy, Planck’s constant, Speed, Wavelength?

A

Photon energy = (Planck’s constant X Speed) / Wavelength

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8
Q

What equation links Photon energy, Emission rate and Power output?

A

Power output = Photon energy X Emission Rate

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9
Q

When comparing two LEDs, what must we consider?

A

The effect of wavelength on power or emission rate and the maximum emission rate

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10
Q

How do you calculate the kinetic energy of a free electron after a collision?

A

(Kinetic energy at current energy level - Kinetic energy at excited energy level) + Kinetic energy of free electron

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11
Q

What is the role of mercury vapour in a fluorescent tube?

A

It emits photons of UV light following ionisation or excitation

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12
Q

Which particle has a greater kinetic energy? Muon or electron?

A

Muon

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13
Q

Which particle has a longer de Broglie wavelength? Muon or electron?

A

Electron

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14
Q

How do atoms gain energy to get excited?

A

Collision of another particle, giving them enough kinetic energy for excitation, or absorption of photons

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15
Q

How do atoms lose energy to get de-excited?

A

Emission of photons

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16
Q

What equation links voltage, charge and work done?

A

Work done = Charge X Voltage

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17
Q

What equation links electrons per second, current and charge?

A

Electrons per second X Charge = Current

18
Q

What happens to the stopping potential as maximum kinetic energy increases?

A

Stopping potential increases

19
Q

What must electrons provide to cause excitation?

A

Enough kinetic energy

20
Q

What does high potential difference produce?

A

High energy electrons

21
Q

What does coating the tube do to the electrons in the coating?

A

It excites the electrons as photons are absorbed

22
Q

When is constant current reached?

A

All photoelectrons released each second reach anode

23
Q

What do photoelectrons lose and gain when potential difference is negative?

A

They lose kinetic energy and gain potential energy

24
Q

How do you calculate maximum kinetic energy?

A

Maximum kinetic energy = Photon energy - Work function

25
Q

How do you convert from eV to J?

A

Divide eV value by 1.6 x 10^-19

26
Q

What equation links kinetic energy, mass, speed?

A

Kinetic energy = 0.5 x Mass x (Speed)^2

27
Q

What is meant by an antiparticle?

A

Particle with equal energy and mass but opposite charge, baryon and lepton numbers

28
Q

What type of energy is discrete?

A

Emitted photon energy

29
Q

How is a photon produced?

A

When atomic electrons move to lower energy levels

30
Q

What must the kinetic energy of the emitted electrons be compared to the energy of the photons?

A

The kinetic energy of each must be less than the energy of the photons

31
Q

What would particle behaviour produce?

A

A patch of light

32
Q

What does graphite cause electron waves to do?

A

Spread out

33
Q

When does maximum intensity occur?

A

When waves are in phase

34
Q

What equation links work function, wavelength, speed, kinetic energy, Planck’s constant?

A

Kinetic energy = ((Planck’s constant X Speed) / Wavelength) - Work function

35
Q

What is the usual state of an electron in energy level 0?

A

Free state

36
Q

What is the usual state of an electron in the lowest energy level?

A

Ground state

37
Q

What needs to be supplied for an electron to be free?

A

Energy

38
Q

How does a spectrum become visible?

A

Excited electrons moving into the lower level, which results in photons

39
Q

When an atom de-excites, how much energy will the photon emitted have?

A

The same as the energy difference between the levels

40
Q

What is the work function?

A

Minimum energy needed to remove an electron from a surface

EM Radiation and Quantum Phenomena (1 decks)

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