--%>
Assignment Help - homework help

Explain Photoelectric effect

Photoelectric effect: An effect described by A. Einstein that demonstrates that light seems to be made up of particles, or photons. The light can excite electrons (termed as photoelectrons in this context) to be ejected from the metal. Light with a frequency below with a certain threshold, at any intensity, will not origin any photoelectrons to be emitted from metal. Above the frequency, photoelectrons are emitted in proportion to the intensity of the incident light.

The reason is that a photon comprises energy in proportion to its wavelength, and constant of proportionality is the Planck’s constant. Below a certain frequency -- and therefore below a certain energy -- the incident photons do not contain enough energy to knock the photoelectrons out of the metal. Over that threshold energy, termed as the work function, the photons will bang the photoelectrons out of the metal, in proportion to the number of photons (that is the intensity of the light). In higher energies and frequencies, the photoelectrons ejected get a kinetic energy equivalent to the difference among the photon's energy and the work function.

   Related Questions in Physics

  • Q : Define Singularity Singularity : The

    Singularity: The center of a black hole, where the curvature of space-time is maximal. At singularity, the gravitational tides deviate; no solid object can yet theoretically survive beating the singularity. Though singularities usually predict inconsi

    		•
  • Q : What is Beauty criterion Beauty

    Beauty criterion (Dirac) - The idea that more aesthetically pleasing a theory is the superior it is. In nature this criterion does not stand up to the actual test -- whether or not forecasts of a given theory agree with observational tests -- however

    		•
  • Q : Free fall acceleration What do you mean

    What do you mean by the term free fall acceleration? State its significance in brief?

    		•
  • Q : Define Tipler machine Tipler machine:

    Tipler machine: The solution to Einstein's equations of general relativity which permits time travel. A tremendously dense (that is, on the order of the density of neutron star matter), infinitely-long cylinder that rotates very quickly can form close

    		•
  • Q : Define Hertz or SI unit of frequency

    Define Hertz or SI unit of frequency: Hertz: Hz (after H. Hertz, 1857-1894): The derived SI unit of frequency, stated as a frequency of 1 cycle per s; it therefore has units of s-1.

    		•
  • Q : Explain Curie-Weiss law Curie-Weiss law

    Curie-Weiss law (P. Curie, P.-E. Weiss): A more broad form of Curie's law that states that the susceptibility, khi, of a paramagnetic substance is associated to its thermodynamic temperature T by the equation:

    Q : What is Standard quantum limit Standard

    Standard quantum limit: It is the limit obligatory on standard techniques of measurement by the uncertainty principle in quantum mechanics.

    		•
  • Q : Calculate the concentration A

    A dual-wavelength spectrometer uses 780 nm and 830 nm. The molar extinction coefficients for oxy-hemoglobin (HbO2) and deoxy-hemoglobin (Hb) at these two wavelengths are: e_HbO2_780nm = 710 cm-1M-1, e_Hb_780nm = 1075 cm

    		•
  • Q : Describe Wien displacement law Wien

    Wien displacement law: For a blackbody, the product result of the wavelength corresponding to the maximum radiances and the thermodynamic temperature is constant, then the Wien displacement law constant. As an outcome, as the temperature increases, th

    		•
  • Q : Dielectric Materials Dielectric is a

    Dielectric is a material in which energy can be accumulated. Ideally, it  is  a non-conductor  of  electric  charge  like  insulators, but  an  efficient   supporter  of  electrostatic  fields. The

    		•