CBSE Class 12 Physics – Dual Nature of Radiation and Matter

Chapter Overview

This chapter explores light and matter’s dual nature. It starts with the photoelectric effect—light ejecting electrons from metals—which shows light behaves as particles (photons). Einstein’s equation introduces energy quantization. Then de Broglie hypothesizes matter (like electrons) also has wave properties, confirmed by electron diffraction. These insights bridge classical and quantum physics. :contentReference[oaicite:0]{index=0}

Important Keywords

• Photoelectric Effect: Emission of electrons when light of suitable frequency hits metal. :contentReference[oaicite:1]{index=1}
• Work Function (φ): Minimum energy needed to free electrons. :contentReference[oaicite:2]{index=2}
• Stopping Potential (V₀): Minimum reverse potential to stop emitted electrons. :contentReference[oaicite:3]{index=3}
• Threshold Frequency (ν₀): Minimum light frequency to produce photoelectrons. :contentReference[oaicite:4]{index=4}
• Photon: Quantum of light; energy E = hν, momentum p = h/λ. :contentReference[oaicite:5]{index=5}
• de Broglie Wavelength (λ): Wavelength of matter particle: λ = h/p. :contentReference[oaicite:6]{index=6}
• Electron Diffraction: Evidence of matter waves (Davisson–Germer). :contentReference[oaicite:7]{index=7}