Ch.7 - Quantum MechanicsWorksheetSee all chapters
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Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: The optic nerve needs a minimum of 2.0 x 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?

Solution: The optic nerve needs a minimum of 2.0 x 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?

Problem

The optic nerve needs a minimum of 2.0 x 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?

Solution

We’re being asked how many photons of blue light with a wavelength of 475 nm are needed to trigger the optic nerve


Recall that the energy of a photon (E) is given by:


E=hv (1)


where:

h = Planck’s constant (6.626 × 10–34 J • s)

v = frequency (in s–1)


Also, recall that the frequency (v) and wavelength (λ) are related:


λ=cv (2)


where:

c = speed of light (3.0 × 108 m/s)


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