Calculator
Example Data Table
| Known | Value | Unit | Computed Wavelength | Typical Range Note |
|---|---|---|---|---|
| Energy | 1.55 | eV | ~800 nm | Near‑infrared optics |
| Frequency | 5.00e14 | Hz | ~600 nm | Visible light band |
| Wavenumber | 2000 | 1/cm | ~5 μm | Mid‑infrared spectroscopy |
These examples are illustrative; your inputs determine the final precision.
Formula Used
- E = h·c / λ (energy to wavelength)
- f = c / λ (frequency to wavelength)
- σ = 1 / λ (wavenumber, with λ in meters)
- p = h / λ (photon momentum)
Constants used: c = 299,792,458 m/s and h = 6.62607015×10⁻³⁴ J·s.
How to Use This Calculator
- Select the input mode that matches what you measured.
- Enter a positive number and choose the relevant unit.
- Pick output units, decimals, and your rounding preference.
- Press Submit to see results above the form.
- Use Download CSV or Download PDF for reporting.
FAQs
1) What inputs can I use to find wavelength?
You can use photon energy, frequency, wavenumber, or wavelength itself. The calculator converts your input to SI units, then derives wavelength and related quantities.
2) Which constants does the calculator use?
It uses the exact defined values for the speed of light and Planck’s constant. This keeps the engineering conversions consistent across energy, frequency, and wavelength calculations.
3) Why do my results differ from a textbook table?
Differences usually come from rounding, unit choices, or using approximate constants like hc in eV·nm. Adjust decimals, enable scientific notation, and verify your unit selection.
4) Can I convert wavelength back to energy?
Yes. Choose “Wavelength → Derived Values” and enter your wavelength. The tool outputs energy, frequency, wavenumber, and photon momentum from the same wavelength.
5) What is the meaning of wavenumber here?
Wavenumber is the spatial frequency of a wave, defined as 1/λ. Spectroscopy often uses cm⁻¹, which this calculator converts internally to m⁻¹ for consistency.
6) When should I use scientific notation?
Use it for very small or very large quantities, such as Joules or meters at extreme wavelengths. It helps prevent long strings of zeros and improves readability.
7) What does photon momentum mean in practice?
Photon momentum is p = h/λ and is used in radiation pressure and scattering calculations. Shorter wavelengths carry higher momentum, which can matter in precision optical systems.