Physical Nature of Light - StudentsUniversity of Central 光物理性质的中央大学的学生.ppt

Physical Nature of Light Wave-Particle Duality Light has a dual nature In some cases it behaves as a wave In other cases it behaves as a particle Wave-Particle Duality Light has a dual nature Most of the time light behaves as a wave Can simultaneously exhibit both wave theory particle theory Either theory is a simple explanation for something more complex Quantum Physics Coexistence of phenomena which require both a wave and a particle theory quantum model of the atom is much more complex than the traditional model subatomic particles and organized chaos Particle Theory of light Stream of tiny particles Such particles called photons quantum particles of fixed units of energy Particle Theory of light Photons strike objects with a real but very small measurable force Light travels in straight lines and bounces off surfaces much like a ball bouncing off a wall Homemade Thomas Hudson Reeve Pinhole Paper Cameras / A pinhole does not focus an image It acts more as a filter It limits the light which reaches the film to a single path for each subject point Ideal Pinhole Would be so small as to let in only one wave of light for each subject point This would be true if not for the wave properties of light, which cause the light to diffract image will deteriorate as very tiny pinhole sizes are approached Wave Theory of Light Waves vibrating up and down perpendicular to direction of light travel Properties of Color Refraction Diffraction Interference all require the wave theory of light Polarized Light Wave Definition A disturbance, variation, oscillation or movement usually repetitive that transfers energy from point to point Visualized as a moving swell or succession of curves Wave Definition The medium through which the wave travels may experience some local oscillations as the wave passes but the particles in the medium do not travel with the wave The disturbance may take any of a number of shapes Wave Shapes A Wave is described mathematically in terms of it