A lifetime of the first excited state for some atom is τ, calculate natural line width for that line.
The Attempt at a Solution
Well, I could use energy-time uncertainty relation
then ΔE*τ=h , now I can use a relation E=hc/λ
to obitain Δλ=c*τ , which is natural line width.
Now let's say τ=17ms (something like the lifetime of the Fe xiv)
then Δλ=3*10^8*17*10^-3=50*10^5m , this can not be true,
what am I doing wrong ?