Wave-Particle Duality of Light and Electrons

Light as a Wave

• Electromagnetic Waves: Light is a type of electromagnetic wave with oscillating electric and magnetic fields at right angles to each other.
• Properties:
  • Amplitude: Height of the wave.
  • Wavelength: Distance between successive peaks; varies with color.
    • Red light: 620-700 nm
    • Blue light: 450-500 nm
  • Frequency: Number of wave cycles per second; also varies with color.

Diffraction and Interference

• Diffraction Patterns: When light passes through two slits, it creates a diffraction pattern on a screen.
• Interference: Creates alternating bright and dark spots due to constructive and destructive interference.
  • Constructive Interference: Waves in phase, amplitudes add up (bright spots).
  • Destructive Interference: Waves out of phase, cancel each other out (dark spots).
• Conclusion: The ability to create these patterns proves that light can behave as a wave.

Light as a Particle

• Photoelectric Effect: Light can knock off electrons from a metal, showing particle behavior.
  • Blue Light: High enough energy (frequency) to eject electrons.
  • Red Light: Insufficient energy (frequency) to eject electrons.
• Photons: Particles of light that can eject electrons.

Dual Nature of Light

• Wave-Particle Duality: Light exhibits both wave-like and particle-like properties.

Electrons

• Dual Nature: Similar to photons, electrons can behave both as particles and as waves.
• Interference Patterns: Electrons passing through two slits create a diffraction pattern similar to light.
• Charge: Unlike neutral photons, electrons are charged particles.

Conclusion

• Wave-Particle Duality: Both light and electrons exhibit dual nature, capable of behaving as both waves and particles.