Question

In the beginning of the 20th century, the matter wave concept was introduced by:

• A. Broglie
• B. Avogadro
• C. Heisenberg
• D. Einstein

Hint:

De Broglie’s hypothesis led to the development of wave-particle duality, which was fundamental in the study of quantum mechanics.

Answer 1

The Correct Option is A

• Option 1: Broglie - This is the correct answer. In the early 20th century, Louis de Broglie introduced the concept of matter waves, proposing that particles such as electrons also exhibit wave-like properties. This was a significant development in quantum mechanics.
• Option 2: Avogadro - This is incorrect. Amedeo Avogadro is known for Avogadro's law, which relates the number of particles in a gas to its volume, but he did not contribute to the concept of matter waves.
• Option 3: Heisenberg - This is incorrect. Werner Heisenberg is famous for his uncertainty principle, which is a fundamental concept in quantum mechanics, but he did not introduce the matter wave concept.
• Option 4: Einstein - This is incorrect. Albert Einstein made significant contributions to the theory of relativity and the photoelectric effect, but he did not introduce the matter wave concept.

Explanation: 

The concept of matter waves was introduced by Louis de Broglie in 1924. He proposed that all matter, especially particles like electrons, have wave-like properties. This idea was crucial in the development of quantum mechanics and led to the wave-particle duality theory.

Answer 2

Instead of just recalling names and dates, we can check who is actually credited with the equation behind the matter wave idea, wavelength equals Planck's constant divided by momentum, which links a particle's wavelength to its momentum.

1. Broglie: Louis de Broglie is the physicist who proposed that a particle with momentum p should also behave as a wave with wavelength equal to h divided by p, where h is Planck's constant. This equation is exactly the mathematical statement of matter waves, and it carries his name to this day.
2. Avogadro: Avogadro's work gives a relationship between gas volume and the number of molecules, with no equation connecting a particle's momentum to a wavelength anywhere in it.
3. Heisenberg: Heisenberg's equation is about the uncertainty in simultaneously knowing position and momentum, not about a particle carrying an associated wavelength.
4. Einstein: Einstein's photoelectric equation treats light as particles, photons, carrying energy, which is the reverse idea, showing wave-like light behaving as particles, not matter particles behaving as waves.

Only the wavelength-momentum relationship, credited to de Broglie, directly proposes that matter carries wave properties.

So the correct answer is Broglie.