IB Physics Topic E.2.2 De Broglie Wavelength and Diffraction Revision Notes (HL)

IB Physics Topic E.2.2 De Broglie Wavelength and Diffraction Revision Notes (HL) | RevisionDojo

Written by official IB examiners

The De Broglie Hypothesis: Particles as Waves

In 1923, Louis de Broglie proposed a revolutionary idea: particles, such as electrons or protons, can exhibit wave-like properties.
He introduced the concept of the de Broglie wavelength, which relates a particle’s momentum to its wavelength: $$\lambda = \frac{h}{p}$$ where:
1. $\lambda$ is the particle’s wavelength (in meters),
2. $h$ is Planck’s constant $6.63 \times 10^{-34} \, \mathrm{J\,s}$.
3. $p$ is the particle’s momentum $ p = mv $, where $ m $ is mass and $ v $ is velocity.

Note

This hypothesis suggests that all moving particles, no matter how small or large, have an associated wavelength.

Bridging the Classical and Quantum Worlds

The de Broglie hypothesis bridges the classical and quantum worlds.
It shows that particles, which we often think of as discrete points, can behave like waves under certain conditions.
This duality of particles behaving as waves is a fundamental concept in quantum mechanics.

Particle Diffraction: Evidence for Wave Behavior

If particles truly exhibit wave-like properties, we should be able to observe phenomena like diffraction and interference, which are characteristic of waves.
This was experimentally confirmed in 1927 by the Davisson-Germer experiment.

The Davisson-Germer Experiment

In this experiment, electrons were accelerated through a potential difference and directed at a nickel crystal.

Nice try, unfortunately this paywall isn't as easy to bypass as you think. Want to help devleop the site? Join the team at https://revisiondojo.com/join-us. exercitation voluptate cillum ullamco excepteur sint officia do tempor Lorem irure minim Lorem elit id voluptate reprehenderit voluptate laboris in nostrud qui non Lorem nostrud laborum culpa sit occaecat reprehenderit

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit.

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

Unlock the rest of this chapter with a free account

The De Broglie Hypothesis: Particles as Waves

In 1923, Louis de Broglie proposed a revolutionary idea: particles, such as electrons or protons, can exhibit wave-like properties.
He introduced the concept of the de Broglie wavelength, which relates a particle’s momentum to its wavelength: $$\lambda = \frac{h}{p}$$ where:
1. $\lambda$ is the particle’s wavelength (in meters),
2. $h$ is Planck’s constant $6.63 \times 10^{-34} \, \mathrm{J\,s}$.
3. $p$ is the particle’s momentum $ p = mv $, where $ m $ is mass and $ v $ is velocity.

Note

This hypothesis suggests that all moving particles, no matter how small or large, have an associated wavelength.

Bridging the Classical and Quantum Worlds

The de Broglie hypothesis bridges the classical and quantum worlds.
It shows that particles, which we often think of as discrete points, can behave like waves under certain conditions.
This duality of particles behaving as waves is a fundamental concept in quantum mechanics.

Particle Diffraction: Evidence for Wave Behavior

If particles truly exhibit wave-like properties, we should be able to observe phenomena like diffraction and interference, which are characteristic of waves.
This was experimentally confirmed in 1927 by the Davisson-Germer experiment.

The Davisson-Germer Experiment

In this experiment, electrons were accelerated through a potential difference and directed at a nickel crystal.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

Topic A - Space, time and motion5 subtopics

Topic B - The particulate nature of matter5 subtopics

Topic C - Wave behaviour5 subtopics

Topic D - Fields4 subtopics

Topic E - Nuclear and quantum physics5 subtopics

IB Physics E.2.2 De Broglie Wavelength and Diffraction Notes

The De Broglie Hypothesis: Particles as Waves

Bridging the Classical and Quantum Worlds

Particle Diffraction: Evidence for Wave Behavior

The Davisson-Germer Experiment

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

The De Broglie Hypothesis: Particles as Waves

Bridging the Classical and Quantum Worlds

Particle Diffraction: Evidence for Wave Behavior

The Davisson-Germer Experiment

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Topic A - Space, time and motion5 subtopics

Topic B - The particulate nature of matter5 subtopics

Topic C - Wave behaviour5 subtopics

Topic D - Fields4 subtopics

Topic E - Nuclear and quantum physics5 subtopics