Explain the photoelectric effect, when does it occur and what is its significance in understanding the nature of light ? (6)
metal (unlike insulators ) contains free electrons (1)
kinetic energy transferred from the light incident on the surface to the free electrons (1)
The maximum kinetic energy of the electrons depends on the frequency (or wavelength) of light and not on the intensity (1)
SOME of the free electrons will be liberated from the surface (1)
No electrons are liberated from the surface until a certain energy /frequency / wavelength of light is incident ie. the threshold energy /frequency / wavelength . (1)
Proves that light travels in discrete quanta (1)
HR
Related Physics A Level answers
All answers ▸Discuss how the graph of orbital velocities in rotational galaxies against distance from the galactic centre implies the existence of dark matter.
Define electrical resistance
How would you calculate the moment of a Force on a rigid object?
A child is standing on a walkway that is moving at 2 metres per second and decides to turn around and walk back to the start at 2 metres per second. Explain why the child cannot reach the start of the walkway at this speed.