Huygens’ Principle – “each point on the leading surface of a wave disturbance may be regarded as a secondary source of spherical waves, which themselves progress with the speed of light in the medium and whose envelope at later times constitutes the new wave front”
Wave Theory Allowed http://physics.tamuk.edu/~suson/html/4323/geometry.html
Light is made of small particles Photons obey same laws of physics for masses Photons are so small that when two particle beams intersect they don’t rebound off of each other Particle Theory of Light http://galileo.phys.virginia.edu/classes/609.ral5q.fall04/LecturePDF/L20-LIGHTII.pdf
Philip Lenard put two pieces of metal in a vacuum. They were part of a circuit, as shown in the illustration.
The plate opposite the plate that the light would shine on was negatively charged, so only very energetic electrons would reach the other side.
When he shined high-frequency light on the metal, electrons were released, completing the circuit.
But the low-frequency light did not have enough energy to get past the negatively-charged plate and contribute to the current
Using this, Albert Einstein hypothesized that light was made of quantized photons, which explains why the frequency of the light affected the energy of the electrons.
Einstein won the Nobel Prize by saying that each photon energized each electron. He won the Nobel for this hypothesis.
Photons Shot through one slit Create a single band on the detector plate Consistent with a particle pattern Shot through two slits Creates a pattern on plate consistent with a wave pattern Double Slit Experiment
The photons could be interacting like particles in a wave. Double Slit Experiment