Question

A photon of light has a wavelength of about 600 nm (1nm = 1 x 10-9 m). What is the energy of this photon of light?

how do I solve this step by step?

Answer 1

your equation is:

E = (hc/Lambda)

E = energy
h = planck's constant (6.626 × 10^-34 joule·s)
c = speed of light (2.998 × 10^8 m/s)
lambda = wavelength

1)
h*c = 1.99 × 10^-25 joules-m
note: when dealing with photons and electrons, we usually use electric volts (eV) instead of Joules(J) as our units.

1eV = 1.602 × 10-19 J
Therefore:
hc = (1.99 × 10^-25 joules-m) × (1ev/1.602 × 10^-19 joules) = 1.24 × 10^-6 eV-m
hc = 1.24 * 10^6 eV-M

2)
Change hc to µm to compensate for the wavelenth

(1.24 * 10^6eV-m) * (10^6 µm/ m) = 1.24 eV-µm
hc = 1.24

3)
change 600nm to µm (micro meter)
600nm = 0.6µm
E = (1.24µm/0.6µm)
E = approx. 31/15eV