CEM 141 MSU EXAM 2 QUESTIONS AND
ANSWERS WITH SOLUTIONS 2024
Lights acts as what? - ANSWER Particle and wave.
Wavelength - ANSWER The distance (m) of waves from peak to peak. Short: x-ray (red), long: infrared
(blue)
Short - higher energy
Long - lower energy
Frequency (V) - ANSWER The number of wavefronts per second. Highest: x-ray
Velocity of Light - ANSWER C = 3.00 X 10^8
= wavelength X frequency
Amplitude - ANSWER The intensity, height of peaks of waves. Highest: blue light
Energy of Wave (J) - ANSWER Increases as frequency increases and as wavelength decreases. Highest: x-
ray
Range of Wavelengths - ANSWER 10^-16 - 10^8 = 24. Only a third are visible
Black Body Radiation - ANSWER When a mass is heated it emits a type of EM radiation, at very high
temps the mass becomes "white hot" because all wavelengths of visible light become equally intense
Photoelectric Effect - ANSWER Metals emit electrons when electromagnetic radiation shines on the
surface, light is transfers energy to the electrons at the metal's surface where it's transformed into KE
that gives the electrons enough energy to leave the atom
Depends on frequency not intensity
, How many electrons are emitted if the light is below it's threshold frequency no matter the intensity? -
ANSWER None.
What increases the number of electrons to be emitted by the photoelectric effect? - ANSWER Intensity.
A particle that transfers light energy with a definable energy, emits one electron
energy of = h (6.626 x 10^-34 J) - ANSWER Photon.
Energy of light equation? - ANSWER E = hV.
h - ANSWER Planck's constant, the energy of a photon.
What happens to the energy when there is a short wavelength? - ANSWER High energy.
Light from the sun (white light) can be separated by a prism to create this, only a small part of the full
EM spectrum? - ANSWER Visible Spectrum.
Atomic Emission Spectrum - ANSWER Spectrum that emits photons, energy diagram: electron goes down
energy levels.
Atomic Absorption Spectrum - ANSWER Spectrum that absorbs photons, energy diagram: electrons goes
up in energy levels.
Heisenberg Uncertainty Principle - ANSWER Principle states that we can't accurately measure both the
position and the energy of a small particle (electron)
Bohr's model did - why its wrong.
Schrodinger's Wave Equation - ANSWER Treated electron as waves derived by mathematical descriptions
of energies.
Psi = wave function of an electron
Psi^2 = probability of finding an electron.
ANSWERS WITH SOLUTIONS 2024
Lights acts as what? - ANSWER Particle and wave.
Wavelength - ANSWER The distance (m) of waves from peak to peak. Short: x-ray (red), long: infrared
(blue)
Short - higher energy
Long - lower energy
Frequency (V) - ANSWER The number of wavefronts per second. Highest: x-ray
Velocity of Light - ANSWER C = 3.00 X 10^8
= wavelength X frequency
Amplitude - ANSWER The intensity, height of peaks of waves. Highest: blue light
Energy of Wave (J) - ANSWER Increases as frequency increases and as wavelength decreases. Highest: x-
ray
Range of Wavelengths - ANSWER 10^-16 - 10^8 = 24. Only a third are visible
Black Body Radiation - ANSWER When a mass is heated it emits a type of EM radiation, at very high
temps the mass becomes "white hot" because all wavelengths of visible light become equally intense
Photoelectric Effect - ANSWER Metals emit electrons when electromagnetic radiation shines on the
surface, light is transfers energy to the electrons at the metal's surface where it's transformed into KE
that gives the electrons enough energy to leave the atom
Depends on frequency not intensity
, How many electrons are emitted if the light is below it's threshold frequency no matter the intensity? -
ANSWER None.
What increases the number of electrons to be emitted by the photoelectric effect? - ANSWER Intensity.
A particle that transfers light energy with a definable energy, emits one electron
energy of = h (6.626 x 10^-34 J) - ANSWER Photon.
Energy of light equation? - ANSWER E = hV.
h - ANSWER Planck's constant, the energy of a photon.
What happens to the energy when there is a short wavelength? - ANSWER High energy.
Light from the sun (white light) can be separated by a prism to create this, only a small part of the full
EM spectrum? - ANSWER Visible Spectrum.
Atomic Emission Spectrum - ANSWER Spectrum that emits photons, energy diagram: electron goes down
energy levels.
Atomic Absorption Spectrum - ANSWER Spectrum that absorbs photons, energy diagram: electrons goes
up in energy levels.
Heisenberg Uncertainty Principle - ANSWER Principle states that we can't accurately measure both the
position and the energy of a small particle (electron)
Bohr's model did - why its wrong.
Schrodinger's Wave Equation - ANSWER Treated electron as waves derived by mathematical descriptions
of energies.
Psi = wave function of an electron
Psi^2 = probability of finding an electron.
