A laser generates a pulse at 450 nm containing 2.75 × 10^15 ​ ​​ photons. What is the energy of the pulse?

Answer 1

If we let λ=the wave length (450nm) and c= speed of light the you can use the relation λ*f=c to calculate f, the frequency ot the wave. Then the energy of a single photon is E=h*f. All thats left is calculation of 2.75*10¹⁵

^photons.

^{Make sense?}

^Jim

Answer 2

E = hν for one photon. So for the given number of photons E = 2.75 x 10¹⁵ hν. And, since ν = c/λ, we can substitute accordingly to give: E = 2.75 x 10¹⁵ hc/λ = [(2.75 x 10¹⁵ photons) ((6.63 x 10^-34 J/s photon)(3.00 x 10⁸ m/s)]/[450 nm (1 x 10⁹nm/m)] = 1.22 x 10^-21 J

Answer 3

1. The energy of each photon can be determined from the equation E = h f, where h is Planck's constant and f is the frequency.
2. The frequency can be determined based on its relation to the speed of light (c) and the wavelength (λ): f = c/λ
3. Substituting c/λ for f in the first equation gives: E = hc/λ
4. Thus, the energy of each photon is:
5. E = (6.626x10^-34 J·s)(2.988x10⁸ m/s)/(450x10^-9m) = 4.3997x10^-19 J (per photon)
6. Multiplying by the number of photons gives the total energy:
7. (4.3997x10^-19 J)x(2.75x10^15)= 1.21x10^-3 J