The metastable state for an atom in laser light is_____________?
Correct answer: C. 10-3 sec
- A. 10-4 sec
- B. 10-5 sec
- C. 10-3 sec
- D. 10-8 sec
Explanation
A metastable state has an unusually long lifetime, typically about 10^-3 s, compared with an ordinary excited state of roughly 10^-8 s, allowing atoms to accumulate for population inversion. The likely wrong choice is 10^-8 sec, which is the approximate lifetime of a normal excited state rather than a metastable state.
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About Quantum Theory and Radiation
Quantum theory treats electromagnetic radiation as packets of energy called photons, with energy proportional to frequency through E equals hf. The topic covers Planck's hypothesis, photon momentum, the photoelectric effect, threshold frequency, work function and wave particle duality, distinguishing quantised energy exchange from classical continuous radiation.
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