User Account

All Pages

Population inversion, Physics

Assignment Help:
population inversion
  • The process in which the number of electrons (N2) in a higher energy state called ‘metastable state of an active medium is increased to a value greater than the number of electrons (N1) in the ground state (i.e.N2 > N1) is called population inversion.
  • There are certain special substances or systems in which the electrons, once excited can remain in the higher energy state for longer times.
  • Such systems are called Active systems or Active Media.
  • Active systems are generally compounds or mixtures of different elements.
  • Consider three electronic states 1,2,3, in an active medium. (Refer text book for diagram.
  • Normally Large number of electrons exist in the Lowest energy state called ground state.
  • Let this number be N1 when photons of energy equal to the difference between E3 and E1 are incident, the electrons from state (1) are excited to state (3) because of absorption. But the property of the state (3) is such that the life time of electrons
  • in the state is very short, of the order 10-8 seconds. 
  • Of course most electrons return to state (1) from state (3) by spontaneous emission, but some electrons go to state (2) also.
  • Therefore, the electrons from the state (3) undergo a quick transition to the state (2) by emitting only a small energy (E3 - E2) which is simply absorbed as the thermal energy by the medium itself.

Related Discussions:- Population inversion

Thermodyanamics, Example of state function

Example of state function

Define step - up transformer, A transformer has 124 turns on the  primary c...

A transformer has 124 turns on the  primary coil and 18,600 turns on the  secondary coil. a. Is this a step-down or a step-up  transformer? step-up transformer

Rydberg constant, Rydberg constant (Rydberg): A constant that governs ...

Rydberg constant (Rydberg): A constant that governs the relationship of the spectral line features of an atom by the Rydberg formula. For hydrogen, it is about 1.097 x 10 7 m

What is maser, Q. What is Maser? Give the principle of it. 1) The term...

Q. What is Maser? Give the principle of it. 1) The term MASER for Microwave Amplification through Stimulated Emission of Radiation. 2) The working of maser is similar to th

Physics project of12, to demonstrate the electrostatic shielding

to demonstrate the electrostatic shielding

Evaluate tha power consumption bulb in series, Two students, A and B, livin...

Two students, A and B, living in neighbouring college rooms, decided to economise by connecting their ceiling lights in series. They agreed that each would install a 100-W bulb

Optical activity and optical rotation, Q.   What is "optical activity and o...

Q.   What is "optical activity and optical rotation"? Write the laws of optical activity of optically active solution. Optical Activity If a plane polarized light is made

Can an electron be obtained from the nucleus, Can an electron be obtained (...

Can an electron be obtained (or come out) from the nucleus? Yes, electron having energy higher than the ordinary atomic electron might be come out of the nucleus because of be

#Radioactivity, why two alpha particles are not released simultaneously in ...

why two alpha particles are not released simultaneously in a radioactive decay???

Equilibrium of charge, A charge is said to be in equilibrium, if total forc...

A charge is said to be in equilibrium, if total force performing on it is zero. A operation of charges is said to be in equilibrium if every charge is independently is equilibrium.

Write Your Message!

Captcha
Order Assignment

Featured Services

Order Now

Popular Subjects

Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

Submit Assignment

Academics

Major Subjects

Majors

Get In Touch

whatsapp: +91-977-207-8620

Phone: +91-977-207-8620

Email: [email protected]

TERMS & POLICIES

HELP & SUPPORT

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd