photoelectric effect emission

The Photoelectric Effect - There are three ways in which electrons eject out of a material. They are (i) Thermionic emission (ii) Field emission (iii) Photo electric emission In all the above cases, energy is given to the material but in different f..

When electromagnetic radiation strikes on the surface of alkali metals, they emit electrons. This is called the photoelectric effect. This occurs as alkali metals have low ionization energies, which allows the electrons to be easily ejected when exposed to light. Among alkali m..

Dual Nature of Radiation and Matter..

Thermionic Emission - The emission of particles from a hot filament was first discovered by Thomas Edison in 1883 but the effect was left unexplained until the discovery of the electron by J.J. Thomson in 1897. In Edison's experiment, he inserted a second filament in t..

Positron Emission Tomography (PET) - PET is a sophisticated version of radio isotope scanning. The principle behind PET scanning is as follows. Short - lived radio isotopes such as 1 1 C, 1 3 N or 1 5 O are produced and incorporated into a solution (of glucose) that can be injected into t..

Reasons for Green House Effect - a) Out of total air pollutants to be 1 x 10 1 2 tons, man made pollutants are 5 x 10 8 tons. b) 25% of world's green house gases are released by USA which supports 4% of global population. c) Carbon monoxide accounts for 50% air pollution d) Suspended part..

's. Methane traps over 21 times more heat per molecule than carbon dioxide. Nitrous oxide absorbs 270 times more heat per molecule than carbon dioxide. Further only long-lived gases have the potential for affecting the global environment. This effect arises principally because the concent..

The graph shows the variation of stopping potential with frequency in accordance to the above equation. The above experimental study can be summarized as follows: Before that, let us recollect some of the parameters and their symbols. V 0 - Stopping potential u 0 - Threshold potential f - Work func..

When light of sufficiently small wavelength is incident on a metal surface, electrons are ejected from the metal. This phenomenon is called as 'photoelectric effect' and the ejected electrons are called as 'photoelectrons..

According to wave theory when light falls on a metal surface, energy is continuously distributed over the surface. All the free electrons receive light energy and when the energy received exceeds that of work function, an electron may escape the surface. If we user a low intensity source, it may ta..