Einstein''s photoelectric equation, Physics

Q. What is Einstein's photoelectric equation? Explain the laws of photoelectric effect with the help of this equation.

Photoelectric Effect : The emission of electron from a metal plate when illuminated by light of any other radiation of suitable wavelength or frequency is called photoelectric effect.

This is one of the experimental evidences of quantum particle nature of light or radiation. This effect was discovered by Hertz when ultraviolet light was allowed to fall on a zinc plate. He observed that electrons are emitted when light of certain frequency is incident on plate as shown in Fig. the electrons so emitted are known as photoelectrons and the current, so produced due to flow of photoelectrons is termed as photoelectric current.

Experimental Set up to Study Photoelectric Effect : Fig. Shows a typical setup used to study photoelectric effect. In an evacuated tube, two electrodes P1 and P2 are connected to an external electric circuit to provide desired potential difference. Electrode P1 behaves as anode and P2 behaves as cathode.

These two electrodes are connected to a microammeter, commutator, voltmeter and a battery as shown in Fig. Microammeter is used to measure current produced due to the flow of photoelectrons, thus current is not very big quantity so we use a very sensitive microammeter to measure it.

Commutator is used to change the polarity of potential on the plates i.e. P1 and P2 can be made positive or negative with respect to each other with the help of commutator. Potential difference between these two metal plates can be measured with the help of commutator. Potential difference between two metal plates can be measured with the help of voltmeter and the potential difference can be changed with the help of potential divider. Light of different intensities and different frequencies could be made to fall on the plate P1.

Einstein's Photoelectric Equation : According to this theory, light travels in the form of energy packages called photons. The velocity of these photons is equal to that of light and their energy is Hv, where 'h' is Planck's constant and v is the frequency f light. When light falls on a metal surface, a photon is completely absorbed by a single electron is the surface. A part of this energy is used in ejecting the electrons against the attraction of the rest part of energy is given to the electron as their kinetic energy so therefore according to energy conservation law.

Posted Date: 7/11/2012 3:10:57 AM | Location : United States

Related Discussions:- Einstein''s photoelectric equation, Assignment Help, Ask Question on Einstein''s photoelectric equation, Get Answer, Expert's Help, Einstein''s photoelectric equation Discussions

Write discussion on Einstein''s photoelectric equation
Your posts are moderated
Related Questions
Q. State Moseley's law. The frequency of the spectral line in the qualities X-ray spectrum is directly proportional to the square of the atomic number (Z) of the element consid

Particles of the medium implement simple harmonic motion about their mean position in a direction perpendicular to the direction of propagation of wave motion. (i) It goes in th

What is meant by the sensitivity of a potentiometer? A battery E 1 of 4 V and a variable resistance R h are linked in series with the wire AB of the potentiometer. The length

Production of a magnet: Magnets can be produced in a variety of ways, generally the method used is determined by the type of magnet required. Using the stroke method

Why is it easy to fuse hydrogen isotopes deuterium and tritium than ordinary hydrogen?

Kirkwood gaps (Kirkwood): Gaps in the asteroid belt, caused through resonance effects from Jupiter. Identical gaps exist in Saturn's rings, because of the resonance effects of

Evaluate  the uniform speed of gondola? Q. The world's largest ferris wheel with a radius of 50.0 m is located in Yokohama City, Japan. Each of the sixty gondolas on the wheel t

Surface tension can be explained in given possible ways: (i)   The property of a liquid on account of which it tends to keep minimum number of molecules in its free surface is d

In thermodynamics, the Joule-Thomson effect describes a process in which a fluid is forced through a valve or porous plug while kept insulated so that no heat is exchanged with the