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

We can use the formula:

energy of one photon = h * c / λ

where h is Planck's constant, c is the speed of light, and λ is the wavelength of light.

Plugging in the values, we get:

E = (6.626 x 10^-34 J s) * (3.0 x 10^8 m/s) / (480 x 10^-9 m)
   = 4.14 x 10^-19 J

The number of photons is equal to the total energy of the pulse divided by the energy of one photon:

number of photons = energy of pulse / energy of one photon

Plugging in the values, we get:

number of photons = 5.0 x 10^-13 J / 4.14 x 10^-19 J
                  = 1.21 x 10^6 photons
                  
Therefore, the best answer is C) 1.2 × 10^22 photons.

A Laser Emits a 5