The eyes of reptile pass a single visual signal to the brain when the visual receptors are struck by photons of wavelength of 850 nm. If a total energy of 3.15 x 10-14 J is required to trip the signal, what is the minimum number of photons that must strike the receptor?

The minimum number of photons that must strike the receptor is

Explanation:

The relation between energy and wavelength of light is given by Planck's equation, which is:

where,

E = energy of the light =

N= Number of photons = ?

h = Planck's constant =

c = speed of light =

= wavelength of light =

Thus the minimum number of photons that must strike the receptor is