Physics 2.2.3-4 Photon Emission and Wave-Particle Duality

12 flashcards · Physics · by TheoTyson

1. Describe the spectrum of white light

   If you split up white light, it will create a spectrum with all wavelengths of visible light known as a continuous spectrum.

2. Describe line absorption spectra

   If you pass white light through a gas, then the gas will only absorb photons with energies equal to the difference between two energy levels. These wavelengths will then be missing from the continuing spectrum. This displays a continuous spectrum with black lines in corresponding to absorbed wavelengths.

3. Describe line emission spectra

   If you split the light from a source with a prism or grating, then a series of bright lines against a black background are displayed. Each line on the spectrum correspond to a particular wavelength of photon emitted with a discrete amount of energy.

4. What is the evidence for light as a wave?

   Light produces interference and diffraction patterns that can only be explained with waves of light constructively and destructively interfering.

5. What is the evidence for light as a particle?

   The photoelectric effect explained that the photon interacted with an electron in a one to one way, and all the energy was conserved like a particle interaction.

6. What is the evidence for electrons as waves?

   Diffraction patterns are observed when electrons are accelerated electrons through a diffraction grating.

7. What is the effect on diffraction lines when increasing the wavelength?

   Increasing the wavelength of the wave increases the spread of lines in the diffraction pattern.

8. What is the effect on diffraction lines when increasing the electron speed?

   Increasing the electron speed decreases the spread of lines in the diffraction pattern.

9. What is the effect on diffraction lines when increasing the mass?

   Increasing the mass of the particle decreases the spread of lines in the diffraction pattern.

10. When does diffraction of a particle occur?

    When the particle interacts with an object of about the same size as its de Broglie wavelength.

11. What is the de Broglie wavelength equation?

    λ\lambda λ = hmv\frac{h}{mv}mvh​

12. What happened to de Broglie's hypothesis?

    His theory wasn't accepted straight away. It was peer reviewed and tested before he could publish it. Once there was enough evidence it was accepted by the scientific community.