Practice Population Inversion (2.1) - Lasers - Physics-II(Optics & Waves)

Practice: Population Inversion

Lesson 2.1Lasers

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8 questions

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6 sample questions

Question 1.
Define population inversion in your own words.
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Think about the relationship between excited and ground states.
Question 2.
What is the role of pumping in achieving population inversion?
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Remember that it is an external energy input.
3Question 3.
What does population inversion signify in a laser?
- More atoms in ground state than in excited state
- Equal atoms in both states
- More atoms in excited state than in ground state
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Remember the 'N2 > N1' condition.
4Question 4.
True or False: Population inversion occurs naturally in all systems.
- True
- False
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Think about systems at thermal equilibrium.
Question 5.
In a laser medium, if it is observed that there are 1000 atoms in the ground state and you need to achieve population inversion. Calculate the minimum number of atoms that need to be in the excited state.
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Population inversion requires N2 to be greater than N1.
Question 6.
If the energy levels of an atom are such that the ground state has an energy of 0 eV and the excited state has an energy of 2 eV, how much energy is required to temporarily create a population inversion of 500 atoms?
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Focus on the energy difference between the states and total atoms needing excitation.

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