Which of the following scientists postulated that moving particles exhibit wave properties?

Step 1: Analyze the question The question asks who proposed that moving particles (like electrons) have wave properties. This is the idea of wave-particle duality for matter.

Step 2: The concept In 1924, French physicist Louis de Broglie proposed that all moving particles have an associated wavelength, given by:

λ = h / p = h / (mv)

where:

• λ = de Broglie wavelength
• h = Planck's constant (6.63 × 10⁻³⁴ J·s)
• m = mass of the particle
• v = velocity of the particle

This was later confirmed by electron diffraction experiments (Davisson and Germer, 1927).

Step 3: Check each option

• A. Ernest Rutherford: Proposed the nuclear model of the atom (from the alpha-particle scattering experiment). Not matter waves.
• B. Erwin Schroedinger: Developed the wave equation (wave mechanics) after de Broglie's idea. He built on the postulate rather than proposing it.
• C. Frank Hertz: With James Franck, demonstrated discrete atomic energy levels. Not matter waves.
• D. Louis de Broglie: Postulated that moving particles exhibit wave properties. ✔
• E. Werner Heisenberg: Formulated the uncertainty principle and matrix mechanics.

Step 4: Answer The correct option is D. Louis de Broglie.

Exam tip: Link names to ideas:

• Rutherford → nucleus
• de Broglie → broglie = big idea that matter has waves (λ = h/mv)
• Schroedinger → wave equation
• Heisenberg → uncertainty
• Franck-Hertz → energy levels

Whenever you see "matter waves" or "particles behave as waves," think de Broglie.