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? ( h = 1.055 × 10^-34 J • s = 6.59 × 10^-16 eV • s) A) 10^-6 eV B) 10^-5 eV C) 10^-4 eV D) 10^-3 eV E) 10^-2 eV

Question

Quizplus · Accepted Answer

The uncertainty in energy can be calculated as:

ΔE = h/Δt

Where h is the Planck's constant and Δt is the duration of the pulse.

Substituting the given values, we get:

ΔE = (1.055 × 10^-34 J s)/(30 × 10^-12 s)
ΔE = 3.52 × 10^-21 J

To convert this to electron volts (eV), we can use the conversion factor:

1 eV = 1.602 × 10^-19 J

Therefore,

ΔE = (3.52 × 10^-21 J) / (1.602 × 10^-19 J/eV)
ΔE = 0.022 eV

Rounding this to one significant figure, we get:

ΔE ≈ 0.02 eV

Which is equivalent to:

ΔE ≈ 10^-5 eV

Therefore, the closest answer choice is B, 10^-5 eV.

A Laser Produces a Beam of 4000-Nm Light