1 electronvolt
1 eVEnergy · definition
The quantity is exact as entered. Comparisons use the clearly stated specimen, model or nominal measurement.
Energy
Just how much energy is 1 electronvolt?
Molecular
1 eV
ENERGY STORED OR TRANSFERRED
1 electronvolt
The quantity is exact as entered.
1 eVEnergy
0
Strontium-87 optical clock transition
The strontium-87 optical clock transition is an energy change between two quantum states of strontium atoms that can set the timing of an optical atomic clock.
1.779 eVClock-transition photon energy
0
Bar length represents energy. Equal energy does not imply the same temperature, power or usefulness.
A little perspective
The clock-transition photon energy of the strontium-87 optical clock transition is about 1.78 times 1 electronvolt.
Measurements, assumptions & sources +
1 electronvolt
Energy: 1 eV; definition.
The quantity is exact as entered. Comparisons use the clearly stated specimen, model or nominal measurement.
Strontium-87 optical clock transition
Clock-transition photon energy: 1.779 eV; measured reference; range 1.773 eV–1.785 eV.
The strontium-87 optical clock transition carries photon energy near 2.85 × 10⁻¹⁹ J. Frequency shifts depend on controlled experimental conditions.
NIST — Compact strontium optical clock
The marked clock-transition photon energy is calibrated. Unmeasured illustration details are representative.
Measurement details
Why these numbers?
Compare 1 electronvolt with the clock-transition photon energy of the strontium-87 optical clock transition. The notes below explain how each value was chosen.
Strontium-87 optical clock transition
1.779 eVClock-transition photon energy · measured reference · range 1.773 eV–1.785 eV
The strontium-87 optical clock transition carries photon energy near 2.85 × 10⁻¹⁹ J. Frequency shifts depend on controlled experimental conditions.
- Comparing
- Energy ↔ Clock-transition photon energy
- Relative size
- The clock-transition photon energy of the strontium-87 optical clock transition is about 1.78 times 1 electronvolt. The clock-transition photon energy of the strontium-87 optical clock transition is approximately 77.9% greater than 1 electronvolt.
How to read the visual
The diagram uses the recorded measurements. Details outside the marked spans do not set the scale.
- We use 1.779 eV for the clock-transition photon energy of the strontium-87 optical clock transition; the recorded range is 1.773 eV–1.785 eV.
- The clock-transition photon energy of the strontium-87 optical clock transition: This is a measured value; check the notes for its source and scope.
Energy is an amount; power describes the rate of energy transfer or use.
1.6022 × 10⁻¹⁹ Jjoules
4.4505 × 10⁻²⁶ kWhkilowatt-hours
3.8293 × 10⁻²³ kcalkilocalories
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