Question

if a beam of red light and a beam of blue light have exactly the same energy, which beams contains the greater number of photons? Explain in detail please.

Answer 1

Answer:

The beam of red light contains more photons

Explanation:

The energy of a photon is directly proportional to its frequency:

$E=hf$

where

h is the Planck constant

f is the frequency of the photon

In the electromagnetic spectrum, red light has longer wavelength than blue light: this means that red light has lower frequency than blue light (because frequency and wavelength are inversely proportional to each other). So, this means that one photon of red ligth has less energy than a single photon of blue light. Therefore, in order to have two beams with same energy, the beam of red light must contain more photons than the beam of blue light.