Electromagnetic radiation with a wavelength of 531 nm appears as green light to the human eye. The energy of one photon of this light is 3.74 × 10^-19 J. Thus, a laser that emits 1.3 × 10^-2 J of energy in a pulse of light at this wavelength produces how many photons?

• A. 3.48 × 10^16 photons
• B. 1.00 × 10^15 photons
• C. 2.47 × 10^17 photons
• D. 5.00 × 10^18 photons

Answer: (A)

Verified step by step guidance

1. First, understand the relationship between energy, wavelength, and photons. The energy of a single photon can be calculated using the formula: \( E = \frac{hc}{\lambda} \), where \( E \) is the energy of the photon, \( h \) is Planck's constant \( (6.626 \times 10^{-34} \text{ J s}) \), \( c \) is the speed of light \( (3.00 \times 10^8 \text{ m/s}) \), and \( \lambda \) is the wavelength in meters.
2. Given that the energy of one photon is \( 3.74 \times 10^{-19} \text{ J} \), you can use this information directly to find the number of photons emitted by the laser pulse.
3. To find the number of photons, use the formula: \( \text{Number of photons} = \frac{\text{Total energy of pulse}}{\text{Energy per photon}} \).
4. Substitute the given values into the formula: \( \text{Number of photons} = \frac{1.3 \times 10^{-2} \text{ J}}{3.74 \times 10^{-19} \text{ J/photon}} \).
5. Perform the division to calculate the number of photons emitted in the pulse. This will give you the number of photons corresponding to the energy emitted by the laser.