Uncertainty Principle Using ΔEΔt ≥ ħ: a Laser Produces a Beam

Multiple Choice

Uncertainty principle using ΔEΔt ≥ ħ: A laser produces a beam of 4000-nm light. A shutter allows a pulse of light, 30 ps in duration, to pass. Which of the following is closest to the uncertainty in the energy of a photon in the pulse? (ħ = 1.055 × 10^-34 J ∙ s = 6.59 × 10^-16 eV ∙ s)

A) 2 × 10^-6 eV
B) 2 × 10^-5 eV
C) 2 × 10^-4 eV
D) 2 × 10^-3 eV
E) 2 × 10^-2 eV