3.12.2 Wave-Particle Duality Flashcards
What was Huygens’ explanation for light?
He thought that light was a longitudinal wave, where all points on the wavefront are point sources of secondary wavelets that spread out in the forward direction at the speed of the wave
What was Huygens’ explanation for reflection?
As the whole wavefront will not reach the surface at the same time (unless it is travelling along the normal), wavelets spread away from the surface once they reach it, and rejoin with others to reform the reflected wavefront
What was Huygens’ explanation for refraction?
It was assumed that light travels slower in a denser medium, therefore, as it entered a more optically dense medium, it would slow down and therefore bend towards the normal
What was Newton’s explanation for light?
Newton thought light was formed from small elastic particles called corpuscles which were continuously given out by luminous objects in all directions
He thought they had a mass, so luminous objects were constantly losing mass
What was Newton’s explanation for reflection?
Corpuscles collide with the surface and a repulsive force pushes them back, causing their component of velocity perpendicular to the surface to change direction, while their component of velocity parallel to the surface stays the same
Angle of incidence = angle of reflection, so it explains the law of reflection
What was Newton’s explanation for refraction?
As corpuscles enter a denser medium, short-range forces of attraction cause their component of velocity perpendicular to the surface to increase, while the parallel component of velocity stays the same, resulting in the light bending towards the normal, and travelling faster in the denser medium
Why was the acceptance of Huygens’ wave theory of light delayed?
Newton was more reputable at the time
Took time for Newton’s theory to be disproved
What are the flaws in Newton’s corpuscular theory of light?
It couldn’t explain diffraction and it states that light travels faster in denser mediums
