Quantum Physics Flashcards
energy of photons?
E=hf
electronvolt?
one electron volt is the energy transferred when an electron travels through a potential difference of one volt.
W=QV
=1.69*10^-19 * 1
kinetic energy?
when an electron is accelerated through a potential difference, its kinetic energy increases
eV=1/2mv^2
photoelectric effect?
light shines on a metal surface and electrons are released from it.electrons removed are known as photoelectrons
threshold frequency?
minimum energy required to release electrons from the surface of a metal.
f=work function energy/ h
work function?
minimum amount of energy required by an electron to escape from its surface.
effect of changing intensity?
The intensity of the incident radiation is proportional to the rate at which photons arrive at the plate.
relation between frequency and work function?
if energy of a photon is less than the work function it cannot release the electron. energy is proportional to frequency. so a photon with threshold freq will have energy equal to work function
effect of changing frequency and intensity of a photon?
higher frequency= more energetic photons.
higher intensity=more no of photons.
absorption light spectra?
spectra which shows composition of light emitted by hot gases.
emission light spectra?
spectra which shows composition of light emitted by cool gases.
band theory of semi conductor?
In a semiconductor, the valence band is fully occupied by electrons but the conduction band is empty. The bands are close in energy, so some electrons gain enough energy to jump across into the conduction band. As temperature decreases, the number of electrons that can jump into
the conduction band also decreases. This means conductivity decreases, and resistivity increases.
