Question

How many photons of light are released from a 0.500 watt laser that has a wavelength of 585 nm that is on for 10.0 seconds? Given that 1 watt = 1 J/s.

A) 3.21 x 10^18 photons
B) 6.42 x 10^18 photons
C) 9.83 x 10^18 photons
D) 1.54 x 10^18 photons

Answer 1

To calculate the number of photons of light released from the laser, we can use the equation E = nhf, where E is the energy of each photon, n is the number of photons, h is Planck's constant, f is the frequency of the light, and c is the speed of light.

Using the given power and wavelength of the laser, we can calculate the energy of each photon and then divide the total energy by the energy of each photon to find the number of photons. The correct answer is D) 4.63 × 10^18 photons.

Step-by-step explanation:

To calculate the number of photons of light released from the laser, we need to use the equation:

E = nhf

Given:

• Power (P) = 0.500 watt = 0.500 J/s
• Wavelength (λ) = 585 nm = 585 × 10-9 m
• Planck's constant (h) = 6.63 × 10-34 J·s
• Speed of light (c) = 3.00 × 108 m/s

First, we need to calculate the energy of each photon using the given wavelength:

E = nhc/λ

E = (6.63 × 10-34 J·s)(3.00 × 108 m/s) / (585 × 10-9 m)

E = 1.08 × 10-19 J

Next, we can calculate the number of photons released by the laser by dividing the total energy by the energy of each photon:

Number of photons = Power / Energy per photon

Number of photons = 0.500 J/s / 1.08 × 10-19 J

Number of photons ≈ 4.63 × 1018 photons

Therefore, the correct answer is D) 4.63 × 1018 photons.