Physics · University
Photon energy from wavelength
Use hc = 1239.84 eV·nm for the stated numerical convention.
Method and conditions
Use hc = 1239.84 eV·nm for the stated numerical convention.
E = hc/λ
Worked examples
A photon has wavelength 140 nm. Using hc=1239.84 eV·nm, calculate its energy in eV. Round the final result to 4 decimal places if needed. Answer in eV.
Divide the stated hc by wavelength: 1239.84/140.
8.856 eV
A photon has wavelength 815 nm. Using hc=1239.84 eV·nm, calculate its energy in eV. Round the final result to 4 decimal places if needed. Answer in eV.
Divide the stated hc by wavelength: 1239.84/815.
1.5213 eV
Try it
A photon has wavelength 290 nm. Using hc=1239.84 eV·nm, calculate its energy in eV. Round the final result to 4 decimal places if needed. Answer in eV.
A photon has wavelength 280 nm. Using hc=1239.84 eV·nm, calculate its energy in eV. Round the final result to 4 decimal places if needed. Answer in eV.
Check your work
Answers and marking notes
- 4.2753 eV
Divide the stated hc by wavelength: 1239.84/290.
- 4.428 eV
Divide the stated hc by wavelength: 1239.84/280.
Further reading and review references
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