The human eye is a complex sensing device for visible light. the optic nerve needs a minimum of 2.0 × 10−17 j of energy to trigger a series of impulses that eventually reach the brain. how many photons of blue light (475 nm) are needed?

The number of photons needed to get the energy to trigger a series of impulses that eventually reaches the brain is: 48.7 photons

The photoelectric effect is an electron coming out of a metal because of electromagnetic radiation

One type of electromagnetic radiation is light

Electrons can come out of metal because they absorb electromagnetic energy radiated on metals. There is also kinetic energy released from metal, which is according to the equation:

E = hf - hfo

fo = the threshold frequency of electromagnetic waves

Radiation energy is absorbed by photons

The energy in one photon can be formulated as

Where

h = Planck's constant (6,626.10⁻³⁴ Js)

f = Frequency of electromagnetic waves

f = c / λ

c = speed of light

= 3.10⁸

λ = wavelength

Known wavelength 475 nm

475 nm = 475.10⁻⁹ m

We put it in the formula to find this light energy E = h. f

E = h. c /λ

E =: 6,626.10⁻³⁴. 3.10⁸ / 475 .10⁻⁹ m

E = 4.1.10⁻¹⁹

Because this is 1 photon energy, while the minimum energy required is 2.0 × 10⁻¹⁷ J, the number of photons needed is:

number of photons = 2.0 × 10−17 J: 4.1.10⁻¹⁹

number of photons = 48.7

Electromagnetic radiation with wavelength of 745 nm

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The energy of a photon

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The equation E = hf

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the approximate energy of a photon

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The equation for photon energy

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the wavelength of a photon whose energy is twice

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