I need help understanding the Planck equation. I have a few example problems, if I could get just one explained it would help a bunch. Questions: What is the energy of a photon of light with a wavelength of 546 nm? What is the energy of a may lead of photons with a wavelength of 546 nm? What color are the...

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## Answers

Energies and wavelengths of photons......

E = hv .......... since c = λv we can write v = c/λ ....... (1)

E = hc / λ

E = (6.63x10^-34 Js) x (3.00x10^8 m/s) / (546 x 10^-9 m) ....... (2)

E = 3.64x10^-19 J

Light with a wavelength of 546 nm is in the visible part of the electromagnetic spectrum and falls between "green" and "yellow". How about calling the color "yellowish green"? (http://science-edu.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html#blue )

(1) v is the Greek letter "nu" and represents the frequency of the wave in reciprocal seconds, s⁻¹. λ is the Greek letter "lambda" and represents the wavelength in meters. The letter c is the speed of light in m/s. In a vacuum c has the value 3.00x10^8 m/s (to three significant digits). h is Planck's constant, 6.63x10^-34 Js.

(2) When doing the calculation you can break with scientific notation and simply enter 546 nm as "546 nano meters" where "nano" is 10^-9. Therefore, enter "546 EE -9" in your calculator.