Question

1. Why did the quantum theory of light explain the outcome of the photoelectric effect experiment?

a. The quantum theory of light showed why high intensity light was needed to give the electrons enough energy to escape the material
b. The material only ejects electrons when there is enough of a distribution of energy across the surface, as described by quantum theory
c. The quantum theory explained why the waves needed less momentum in order to impact the electrons and knock them off
d. The material only absorbed a certain frequency of the light and the quanta of light are defined by the frequency

2. Why do lamps of different elements have different colored light?
a. The chemicals in the light are not affected by the electricity running through them and are only naturally luminescent
b. They gases have different energy levels that light can be emitted from, which produce different wavelengths (colors) of light
c. The gases chemically bond under the effects of the electricity and the release of the energy from this bonding produces the light colors
d. The electricity from the device is quantized and can only be accepted by certain wavelengths, so the remaining wavelengths are the colors we see

Answer 1

question 1 is option D

question 2 is option B

Explanation for question 1: The quantum theory of light, as proposed by Albert Einstein, explained the outcome of the photoelectric effect experiment by proposing that light travels in discrete packets of energy called photons, and that the energy of a photon is directly proportional to its frequency. In the photoelectric effect, the material only absorbs photons with a certain minimum frequency, called the threshold frequency. When a photon with sufficient energy is absorbed by an electron in the material, the electron is ejected with kinetic energy equal to the energy of the photon minus the energy required to overcome the binding energy of the electron to the material. This explains why increasing the intensity of the light does not increase the kinetic energy of the ejected electrons, but increasing the frequency of the light above the threshold frequency does.

Explanation for question 2: When an electric current is passed through a gas or vapor, some of the electrons in the gas are excited to higher energy levels. When these electrons return to their lower energy levels, they emit light in the form of photons. The energy of the emitted photons corresponds to the energy difference between the excited state and the lower energy state. Different elements have different electron configurations and energy levels, and therefore they emit light at different wavelengths (colors) when excited.

For example, sodium vapor lamps emit yellow light because the excited sodium atoms emit photons with a characteristic wavelength in the yellow part of the spectrum. Mercury vapor lamps emit blue-green light because the excited mercury atoms emit photons with a characteristic wavelength in the blue-green part of the spectrum.