Biology Forums - Study Force

1. Describe how polarizing filters work, and give one example of where they might be used. (3marks)

2. How does the photoelectric effect support the notion of wave- particle duality? ( 3 marks)

They can definitely be used in a camera. Polarizing filters work by blocking certain light waves from entering the lens. Rotating a polarizer allows certain types of light waves to pass through, while blocking other ranges of light waves. Thus, you could turn a sky from light blue to very dark blue or increase/decrease reflections by simply rotating the filter.


I found something for you! I really don't know what this is, so maybe you can make more sense from it.

For #2, in the photoelectric effect, the greater the frequency (frequency should be higher than the threshold frequency) of light greater is the kinetic energy of the emitted electron, it is as if the momentum of the photon is transferred to the electron and hence such a interaction accompanied by transfer of momentum must be between a particle and a particle. photoelectric effect supports the particle nature of light but it doesn't disprove the wave theory. When electrons are made to pass through a thin metal foil it produces a inference pattern on the photographic plate kept adjacent to the metal foil, interference is phenomenon exhibited by waves and hence electron diffraction supports the wave nature of an electron.

In the photoelectric experiment how bright the light is does NOT matter IF the wave length is too long ( frequency is to too small) If light was wave then the brightness would matter because the brighter the light the more electrons would be emitted and frequency/wavelength would NOT matter.

But that is not the way it works. Frequency/wavelength does matter. Below a certain wave length no electrons are emitted. Once you get to that wavelength then brightness does matter.

Thank you all :)