AP BIOLOGY

Detailed explanation-1: -The energy of a single photon is: h or = (h/2) where h is Planck’s constant: 6.626 x 10-34 Joule-sec. One photon of visible light contains about 10-19 Joules (not much!)

Detailed explanation-2: -We know that photon energy is expressed in the electronvolt (eV) unit and the joule. Where, E = photon energy. h = Planck’s constant.

Detailed explanation-3: -A photon is the smallest discrete amount or quantum of electromagnetic radiation. It is the basic unit of all light. Photons are always in motion and, in a vacuum, travel at a constant speed to all observers of 2.998 x 108 m/s. This is commonly referred to as the speed of light, denoted by the letter c.

Detailed explanation-4: -The energy of a photon can be calculated in two ways: If the photon’s frequency is known, we can use the formula E = h f . Max Planck proposed this equation, which is why it is known as Planck’s equation. If the photon’s wavelength is known, the photon’s energy can be calculated using the formula E = h c .

Detailed explanation-5: -Research by a team from Rockefeller University and the Research Institute of Molecular Pathology in Austria has shown that humans can detect the presence of a single photon, the smallest measurable unit of light.