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The Energy of a Photon calculator computes the energy of a photon based on the wavelength (λ), Plank's Constant (h), and the speed of light (c)
INSTRUCTIONS: Choose units and enter the following:
- (λ) Wavelength of light
Energy of a Photon(E): The calculator returns the energy in Joules. However, this can be automatically converted to compatible units via the pull-down menu.
The Math / Science
Certain conditions make it possible to describe light as a particle, or photon[1]. The energy of each photon of light corresponds to a specific frequency. This relationship is described by Planck's equation:
where
- E is the energy of the photon
- h is Planck's constant
- c is the speed of light ( 2.998 × 108 m/s)
- λ is the wavelength of the light
Example
You see a green light with a wavelength of 530nm. Calculate the energy, in joules, associated with a photon of this light.
First, we define our variables:
- λ = 530nm = 5.3 x 10-7 m
- h = 6.626 × 10 -34 joules*s
- c = 2.998 × 108 m/s
E=(hc)/λ
Next, we substitute in our values and calculate the energy:
E = (6.626 × 10 -34 joules*s)(2.998 × 108 m/s) / (5.3 x 10-7m)
E = 3.748 x 10-19 joules
References
Whitten, et al. "Chemistry" 10th Edition. Pp. 137
Chemistry Worksheet: Planck's Equation
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