A laser emits a 5.0 × 10³-J pulse of light that has a wavelength of 480 nm.Determine the number of photons in the pulse.
A)5.2 × 10¹⁶
B)2.5 × 10¹⁹
C)1.2 × 10²²
D)3.1 × 10²²
E)8.1 × 10²⁴

Question

Quizplus · Accepted Answer

The energy of one photon can be calculated using the equation E = hc/λ, where hc is the product of Planck's constant and the speed of light.

E = hc/λ = (6.626 × 10⁻³⁴ J·s)(3.00 × 10⁸ m/s)/(480 × 10⁻⁹ m) = 4.13 × 10⁻¹⁹ J

The number of photons in the pulse can be calculated by dividing the total energy of the pulse by the energy of one photon:

Number of photons = (5.0 × 10³ J)/(4.13 × 10⁻¹⁹ J/photon) = 1.21 × 10²²

Therefore, the answer is C: 1.2 × 10²².

A Laser Emits a 5