Define wave-particle duality .

Wave-particle duality is the phenomenon in which light (and matter) can behave both as waves and as particles .

What phenomenon provides evidence that light behaves as a particle?

The photoelectric effect provides evidence that light interacts with matter as a particle (a photon ).

What phenomenon provides evidence that light behaves as a wave?

The diffraction and interference of light, as shown in Young's double slit experiment, provide evidence that light propagates as a wave.

If the frequency of light is above the threshold frequency and its intensity is increased, what is observed in the photoelectric effect?

More photoelectrons are emitted per second. The kinetic energy of the emitted electrons does not increase with intensity, contradicting the wave theory of light.

What did Louis de Broglie discover about matter such as electrons?

De Broglie discovered that matter , such as electrons, can behave as a wave , evidenced by the diffraction pattern produced when a beam of electrons is directed at a thin graphite film.

Graphite film is used in electron diffraction experiments because of its .......... structure, which provides gaps between atomic planes that act as slits.

Graphite film is used in electron diffraction experiments because of its crystalline structure, which provides gaps between atomic planes that act as slits.

True or False? Increasing the accelerating voltage in an electron diffraction tube increases the diameter of the diffraction rings.

False. A larger accelerating voltage reduces the diameter of the diffraction rings; a lower accelerating voltage increases the diameter of the rings.

Define the de Broglie wavelength .

The de Broglie wavelength is the wavelength associated with a moving particle .

What did de Broglie realise applied to all particles, not just electrons?

He realised that all particles , not just electrons, can show wave-like properties , such as an associated wavelength.

When are quantum mechanical (wave) effects of a particle observable?

When the width of the sample is around the same order of magnitude as the particle's de Broglie wavelength .

A LevelPhysicsCambridge (CIE)Flashcards22. Quantum PhysicsWave-Particle Duality

Wave-Particle Duality (Cambridge (CIE) A Level Physics): Flashcards

Exam code: 9702

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Define wave-particle duality.

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Cards in this collection (14)

Define wave-particle duality.
Wave-particle duality is the phenomenon in which light (and matter) can behave both as waves and as particles.
What phenomenon provides evidence that light behaves as a particle?
The photoelectric effect provides evidence that light interacts with matter as a particle (a photon).
What phenomenon provides evidence that light behaves as a wave?
The diffraction and interference of light, as shown in Young's double slit experiment, provide evidence that light propagates as a wave.
If the frequency of light is above the threshold frequency and its intensity is increased, what is observed in the photoelectric effect?
More photoelectrons are emitted per second. The kinetic energy of the emitted electrons does not increase with intensity, contradicting the wave theory of light.
What did Louis de Broglie discover about matter such as electrons?
De Broglie discovered that matter, such as electrons, can behave as a wave, evidenced by the diffraction pattern produced when a beam of electrons is directed at a thin graphite film.
Graphite film is used in electron diffraction experiments because of its .......... structure, which provides gaps between atomic planes that act as slits.
Graphite film is used in electron diffraction experiments because of its crystalline structure, which provides gaps between atomic planes that act as slits.
True or False?
Increasing the accelerating voltage in an electron diffraction tube increases the diameter of the diffraction rings.
False.
A larger accelerating voltage reduces the diameter of the diffraction rings; a lower accelerating voltage increases the diameter of the rings.
Define the de Broglie wavelength.
The de Broglie wavelength is the wavelength associated with a moving particle.
What did de Broglie realise applied to all particles, not just electrons?
He realised that all particles, not just electrons, can show wave-like properties, such as an associated wavelength.
State the equation relating the de Broglie wavelength λ to a particle's momentum p.
$λ = \frac{h}{p}$
State the equation relating the de Broglie wavelength λ of a particle to its kinetic energy E.
$λ = \frac{h}{\sqrt{2 m E}}$
When are quantum mechanical (wave) effects of a particle observable?
When the width of the sample is around the same order of magnitude as the particle's de Broglie wavelength.
Momentum and kinetic energy of a particle are related by the equation p = ..........
Momentum and kinetic energy of a particle are related by the equation p = $\sqrt{2 m E}$
True or False?
A particle with a greater momentum has a longer de Broglie wavelength.
False.
Since $λ = \frac{h}{p}$ , a greater momentum gives a shorter de Broglie wavelength.

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