An atom can radiate at any time after it is excited. It is found that in a typical case, the average excited atom has a lifetime of about 10^(-8) s. That is, during this period it emits a photon and is de-excited. What is the minimum uncertainty delta-v in the frequency of the photon?
Answer: 8 x 10^6 Hz
Explanation
Using the Heisenberg Uncertainty Principle:
ΔE * Δt >= h/4π
where ΔE = h * Δv (energy uncertainty) and Δt = 10^(-8) s (lifetime)
h * Δv * 10^(-8) >= h/4π
Δv >= 1/(4π * 10^(-8))
≈ 8 x 10^6 Hz
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