Chapter 7 Flashcards
Wave
A disturbance that transmits energy (water, sound, light)
Characteristics of waves
Frequency (v): the number of cycles per second
Wavelength: the distance the wave travels during one cycle
Amplitude: the height of the crest of each wave
Frequency, wavelength units
frequency: 1/s or Hz
wavelength: m or nm
Electromagnetic Radiation
contains an electric and magnetic field perpendicular to each other
- they oscillate in vacuum or matter to transmit energy
Photoelectric effect
the idea that when light strikes a surface of certain metals, electrons are ejected
In what cases does the photoelectric effect not take place
If the frequency of the light is below the minimum threshold, no electrons are ejected regardless of the intensity of the light.
When does the photoelectric effect take place
When the frequency of the light is above the minimum threshold, the maximum kinetic energy of emitted electrons increases linearly with the frequency of the light.
How does the number of electrons emitted and the kinetic energy differ with an increase in intensity above threshold frequency during the photoelectric effect?
Above threshold frequency, the number of electrons emitted increases with the intensity of light whereas the kinetic energy does not depend on the intensity.
Electrons emitted > increase with intensity
Kinetic energy > increases with frequency
What is a photon? Units?
A packet of light or particles of light.
J/photon
What is binding energy?
The minimum energy required to eject an electron
How to find the kinetic energy of an ejected electron?
KE = photon energy (light) - binding energy (min energy)
What does it mean when they say that energy levels in an atom are quantanized?
an atoms can only have certain specific energy values (cannot be continuous)
Ionization Energy
the minimum amount of energy required to remove 1 mole of electrons from a gaseous ground state atoms
