![]() Guide: Move the light source along it, the distance between light source and dark box Light: Source, 12V/35W halogen tungsten lamp. ![]() □□□ + □□ (1) (a) Determination of Plank’s constant by photoelectric measurement instrument Apparatus required:Ĭolor filters (with corresponding wavelength written over it) Structure: TheĮxcess energy of this photon appears as kinetic energy of the electron, so that There is the possibility of ejection of photoelectron, while if □□ < □□, it is impossible. Is greater than an electron’s binding energy, the electron escapes from the metal with a kineticĮnergy equal to the difference between the photon’s original energy and the electron’s binding If the photon energy is less than □□, no electrons are emitted. When a photon strikes a bound electron, it transfers itsĮnergy to the electron. ![]() (V-I plot for different frequencies of radiation)įor each metal, there exists a minimum binding energy for an electron characteristic of theĮlement, also called the work function □□. (Photocurrent variation with intensity of light, and V-I plot for different intensities) The emission of electron occurs within a very short time interval after arrival of the radiationĪnd member of electrons is strictly proportional to the intensity of this radiation. The emission process is strongly frequency dependent.įor each metal, there exists a critical frequency (threshold frequency) such that light of lowerįrequency is unable to liberate electrons, while light of higher frequency always does. To explain blackbody radiation, and □ is the frequency of the photon.Ī schematic of Photoelectric effect set up Of these photons is □ = □□, where □ is the fundamental constant of nature as proposed by Max Planck It is particulate and travels with a discrete amount of energy packets (photons). This interpretation of light was coined byĮinstein in 1905, for which he was awarded the Nobel Prize. Light (radiation) incident upon a metal target emits electrons from it, is termed as photoelectricĮmission or effect and the electrons as photoelectrons. (c) Determination of Planck’s constant from the Light Emitting Diode (LED) Theoretical background: Objective: (a) Determination of Plank’s constant by photoelectric measurement instrument (b) To verify the inverse square law of radiation using a photoelectric cell.
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