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Example Questions
Example Question #1 : Quantum Physics
A laser outputs light of a single color with photon energy . A nonlinear crystal, which halves the wavelength of light, is placed in the path of the laser beam. What is the energy of the photons exiting the crystal?
Halving the wavelength is equivalent to doubling the frequency since for a light wave the wavelength and frequency are related by , where is the speed of light. The energy of a photon is , where is Planck's constant, so the photon energy is doubled.
Example Question #1 : Energy Quantization
A monochromatic light source is incident on a neutral density filter which decreases the light source's intensity by a factor of 3 but does not change its color. What happens to the energy of a photon in the less intense beam?
The photon energy decreases by a factor of 9.
The photon energy decreases only slightly.
The photon energy decreases by a factor of 3.
None of these
The photon energy increases by a factor of 3.
None of these
The photon energy does not change since the color of light (and therefore the frequency of the light) does not change.
Example Question #11 : College Physics
A car with mass is heading toward a wall at a speed . What is the approximate de Broglie wavelength of the car?
The de Broglie wavelength is given by .