Option D Turning Points in Physics Chapter 2 Wave-particle duality Word Newton’s corpuscular theory of light corpuscles reflection refraction plane mirror normal parallel perpendicular velocity longitudinal polarisation Young’s double slit experiment interference coherent source bright fringe dark fringe diffraction transverse electromagnetic waves permittivity of free space permeability of free space phase radio waves transmitter detector loop concave oscillating stationary wave node antinode dipole detector photoelectricity photoelectric emission frequency Definition gold leaf electroscope photoelectrons threshold frequency intensity photon quanta continuous spectrum work function stopping potential monochromatic vacuum photocell wave-particle duality de Broglie wavelength momentum concentric inversely proportional monoenergetic lens aberration transmission electron microscope (TEM) magnetic lens electron gun magnetic condenser lens scanning tunnelling microscope (STM) piezoelectricity piezoelectric transducer