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

What is a neutral buoyancy, Q. What is a neutral buoyancy? Answer:- ...

Q. What is a neutral buoyancy? Answer:- Buoyancy is the net upward force knowledgeable by an object submersed in a fluid. Pascal's principle utters that fluid pressure on

Explain the thermal equilibrium, Explain the Thermal Equilibrium Thermal ...

Explain the Thermal Equilibrium Thermal Equilibrium occurs when one or more substances reach a common temperature by exchanging heat. When two substances come into thermal contac

Define pascal''s law, Pascal's principle describes that if the pressure is ...

Pascal's principle describes that if the pressure is operated at any position in an incompressible liquid it is send undiminished to all other sections in the liquid. In the dia

scientific hypothesis or hypothes, 1. A statement of the scientific hypoth...

1. A statement of the scientific hypothesis/hypotheses you have decided to address in your analyses, with a rationale for each. From the rational of the study, the amount of vit

Force diagrams., draw a force diagram for a baseball player who slows as he...

draw a force diagram for a baseball player who slows as he slides into the base?

Define about the graphite structure, Define about the Graphite Structure ...

Define about the Graphite Structure   Graphite is the allotropic form of carbon. In case of graphite the carbon atoms are arranged in regular hexagons in flat parallel layers a

What is the ohm law, What is the Ohm Law? Ohm discovered that the amoun...

What is the Ohm Law? Ohm discovered that the amount of current was directly proportional to the voltage (more voltage gives more current) and inversely proportional to the resi

Electric field valid for points on the y-axis, Specified the expression bel...

Specified the expression below valid for points in the x-y plane what is the y-component of the electric field valid for points on the y-axis?

Superposition theorem, how to find output voltage by using superposition th...

how to find output voltage by using superposition theorem

Gaia hypothesis, Gaia hypothesis (J. Lovelock, 1969): The idea that as...

Gaia hypothesis (J. Lovelock, 1969): The idea that as a whole Earth should be regarded as a living organism & that biological procedure stabilize the environment.

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