Answer: option C. Red photons have the least amount of energy.
Explanation:
This question deals with the visible light spectrum.
The white light is composed of a mix of colors which, in increasing order of frequency and energy, are named red, orange, yellow, green, blue and violet.
Red light has the least energy and violet light has the most energy.
Light is said to have both characteristics of waves and of particles.
As wave, light has a wavelength, that is inverseley related to its frequency. So, the longer the wavelength the lower the frequency.
This is the equation: wavelength = speed / frequency (λ = c / ν)
Red light, as said, has the largest wavelength and the lowest energy.
Photon is what characterizes the light as a particle: a photon is a quantum of light.
And the energy, E, of a photon is directly related to the frequency as per this equation: E = hν, where h is Planck's constant.
So, that equation shows that the lowest the frequency, ν, the lowest the energy of the photon. This summarizes the said about the photon energy and the color of light:
red light: longest wavelength → lowest frequency → least energy
violet light: shortest wavelength → highest frequency → most energy.
This table, taken from internet, shows the wavelength, frequency and photon energy of the visible light:
Color Wavelength Frequency Photon energy
Violet 380–450 nm 668–789 THz 2.75–3.26 eV
Blue 450–495 nm 606–668 THz 2.50–2.75 eV
Green 495–570 nm 526–606 THz 2.17–2.50 eV
Yellow 570–590 nm 508–526 THz 2.10–2.17 eV
Orange 590–620 nm 484–508 THz 2.00–2.10 eV
Red 620–750 nm 400–484 THz 1.65–2.00 eV
The bottom line shows the explained: the red photons have the least amount of energy (option C.)
