MHT-CET : Physics Entrance Exam

### MHT - CET : Physics - Electrons and Photons Glossary

·         Specific Charge of an Electron: The ratio of charge on an electron to its mass is called the specific charge of an electron.

·         Photoelectric Effect: The phenomenon of emission of electrons by a metal surface, when light is incident upon it, is called photoelectric effect.

·         Photoelectrons: The electrons emitted by a metal surface, when light is incident upon it, are called photoelectrons.

·         Threshold Frequency: The minimum frequency of incident radiation at which photoelectrons are emitted by a surface is known as threshold frequency. It is usually denoted by the symbol n0.

·         Work Function: The minimum energy which the incident radiation must possess to liberate photoelectrons from a photosensitive surface is known as the work function of that surface. It is usually denoted by the symbol Æ or W0. Its relation with the threshold frequency is given by the equation

h
n0 = Æ.

·         Stopping Potential: The value of the reverse (negative) potential which reduces the photoelectric current to zero is known as the stopping potential.
OR
The value of the stopping potential which just stops the photoelectrons with the maximum energy from reaching the collector of a photoelectric cell is known as the stopping potential. It is usually denoted by the symbol vs or v0.

·         Photoelectric Cell: Photoelectric cell is a device which converts light energy into electrical energy and which works on the basis of the photoelectric effect. Its symbol is as follows:
.

·

·         Threshold Wavelength: The maximum (longest) wavelength of incident radiation at which photoelectrons are emitted by a surface is known as the threshold wavelength. It is usually denoted by the symbol l0. Its relation with the threshold frequency is given by the equation

l0 =

 c n0

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