De Broglie wave length, lambda=h/mv

In summary, the De Broglie formula assigns a wavelength to each massive body, but for objects with large masses and high speeds, the calculated wavelength may go beyond the Planck length which is considered the limit. This makes it impossible to observe quantum effects on these objects, as the de Broglie wavelength needs to be large enough to have observable effects. This is due to the fact that these objects are made up of a large number of particles, making it necessary to think about the calculations rather than blindly plugging in values to a formula.
  • #1
matteo16
28
0
for each massive body is assigned a wave length by the De Broglie formula: lambda=h/mv

but, for example, a stone which has a mass of 10 kg and which is moving with a speed of 100 m/s, is assigned a wave length that goes beyond the Planck length that is the limit.
how is this possible?
thus, if i want to see the QM effects on it i would to observe it at a distance lower than the Planck length
and this is impossible.
 
Physics news on Phys.org
  • #2
Planck Length = 1.6 × 10^−35 meters

In your case, lambda = 1.05 x 10^-37 meters.

I don't see how this "goes beyond the Planck length". To see QM effects, the de Broglie wavelength has to be large enough to give observable effects.
 
  • #3
scarecrow said:
Planck Length = 1.6 × 10^−35 meters

In your case, lambda = 1.05 x 10^-37 meters.

I don't see how this "goes beyond the Planck length". To see QM effects, the de Broglie wavelength has to be large enough to give observable effects.

1.05 x 10^-37 meters is lower than 1.6 x 10^-35(that is the limit) and so how this is possible?
how can this value surpass the limit?
 
  • #4
for one thing, a stone is a macroscopic object, it is made up of a large number of "more fundemental" particles. you plug blindly into a formula (this could be called "proceeding formally") and you get an answer than doesn't make sense to you. this means you have to think about what you are doing and not just plug into a formula.
 
  • #5
matteo16 said:
for each massive body is assigned a wave length by the De Broglie formula: lambda=h/mv

but, for example, a stone which has a mass of 10 kg and which is moving with a speed of 100 m/s, is assigned a wave length that goes beyond the Planck length that is the limit.
how is this possible?
thus, if i want to see the QM effects on it i would to observe it at a distance lower than the Planck length
and this is impossible.

That is right And that is one possible reason why nothing larger than a small molecule has ever demonstrated quantum effects.
 

What is the De Broglie wavelength?

The De Broglie wavelength, also known as the matter wave, is a concept in quantum mechanics that describes the wavelength associated with a particle. It is named after physicist Louis de Broglie, who proposed that all matter has both particle-like and wave-like properties.

What is the formula for calculating the De Broglie wavelength?

The formula for calculating the De Broglie wavelength is lambda = h/mv, where lambda is the wavelength, h is Planck's constant, m is the mass of the particle, and v is the velocity of the particle.

How does the De Broglie wavelength relate to the uncertainty principle?

The De Broglie wavelength is related to the uncertainty principle, which states that the more accurately we know the position of a particle, the less we know about its momentum, and vice versa. This means that as the wavelength of a particle becomes smaller, its momentum becomes more uncertain.

What is the significance of the De Broglie wavelength?

The significance of the De Broglie wavelength is that it helps us understand the wave-particle duality of matter. It also allows us to calculate the wavelength of a particle and determine its quantum behavior, which is essential in understanding the behavior of subatomic particles and atoms.

How is the De Broglie wavelength experimentally observed?

The De Broglie wavelength can be experimentally observed through a phenomenon called electron diffraction, where electrons are diffracted by a crystal lattice, similar to how light is diffracted by a grating. The resulting pattern can be used to calculate the wavelength of the electron and confirm the De Broglie hypothesis.

Similar threads

  • Quantum Interpretations and Foundations
Replies
1
Views
1K
  • Quantum Interpretations and Foundations
Replies
17
Views
3K
  • Quantum Interpretations and Foundations
Replies
4
Views
999
  • Quantum Interpretations and Foundations
Replies
28
Views
4K
  • Quantum Interpretations and Foundations
Replies
14
Views
4K
  • Quantum Interpretations and Foundations
Replies
12
Views
1K
  • Other Physics Topics
Replies
5
Views
726
  • Quantum Interpretations and Foundations
Replies
1
Views
1K
  • Quantum Interpretations and Foundations
Replies
2
Views
3K
  • Quantum Interpretations and Foundations
Replies
28
Views
7K
Back
Top