The optic nerve needs a minimum of 2.0 ×10^-17 J of energy to trigger a series of impulses that

Name: Problem 64, Chapter 7: CHEMISTRY: The Molecular Nature of Matter and Change
Uploaded: 2020-06-23T21:04:35-08:00
Duration: 4 min 30 s
Channel: Ashley Moorman
Description: 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. (a) How many photons of red light ( 700 . nm ) are needed? (b) How many photons of blue light (475 nm)?

step 1 Okay, so the energy of one photon, so we're going to call this 1P, or I guess I'm going to write

Question

The optic nerve needs a minimum of $2.0 \times 10^{-17} \mathrm{~J}$ of energy to trigger a series of impulses that eventually reach the brain. (a) How many photons of red light ( $700 . \mathrm{nm}$ ) are needed? (b) How many photons of blue light (475 nm)?

   The optic nerve needs a minimum of $2.0 \times 10^{-17} \mathrm{~J}$ of energy to trigger a series of impulses that eventually reach the brain.
(a) How many photons of red light ( $700 . \mathrm{nm}$ ) are needed?
(b) How many photons of blue light (475 nm)?

CHEMISTRY: The Molecular Nature of Matter and Change

Martin S.… 9th Edition

Chapter 7, Problem 64

Instant Answer

Solved by Expert Ashley Moorman

06/23/2020

Step 1

We can use the formula: E = (hc) / λ where E is the energy of a photon, h is Planck's constant (6.63 × 10^-34 Js), c is the speed of light (3.0 × 10^8 m/s), and λ is the wavelength of the light. (a) For red light (700 nm): λ = 700 × 10^-9 m E_red = (6.63 × Show more…

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The optic nerve needs a minimum of $2.0 \times 10^{-17} \mathrm{~J}$ of energy to trigger a series of impulses that eventually reach the brain. (a) How many photons of red light ( $700 . \mathrm{nm}$ ) are needed? (b) How many photons of blue light (475 nm)?

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Key Concepts

Planck's Equation

Planck's Equation (E = hc/?) relates the energy of a single photon to its wavelength, with h as Planck's constant and c as the speed of light. This equation is fundamental in determining how the energy of light varies with wavelength, thereby allowing calculation of the energy of individual photons.

Photon Energy

Photon energy is the discrete amount of energy carried by a photon, which is inversely proportional to its wavelength. In this context, it explains why blue light (with a shorter wavelength) has more energy per photon compared to red light (with a longer wavelength).

Energy Partitioning

Energy partitioning involves dividing the total energy required to trigger the optic nerve by the energy of a single photon to determine the number of photons needed. This concept bridges quantum-level phenomena with macroscopic energy requirements in biological systems.

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