Convert Attojoules to Watt-Hours
Convert Attojoules (aJ) to Watt-Hours (Wh) instantly and accurately.
Conversion Formula
Wh = aJ × 2.777777778e-22
About Attojoules
An attojoule (aJ) is 10⁻¹⁸ J - the scale of individual X-ray photons and superconducting qubit circuits. A 1 keV X-ray photon carries 160 aJ; a visible green photon (~550 nm) carries ~0.36 aJ. Josephson junction energies in superconducting qubits are set in tens to hundreds of aJ to achieve quantum coherence at millikelvin temperatures. XRISM's cryogenic TES X-ray spectrometer resolves individual photon energies at the hundreds-of-aJ level with ~7 eV FWHM resolution. 1 aJ = 10⁻¹⁸ J = 6.242 eV.
About Watt-Hours
A watt-hour (Wh) is the energy delivered by 1 watt for one hour - exactly 3,600 J. It is the practical unit for small-scale electrical energy: a 10,000 mAh 5 V power bank stores 50 Wh; a laptop battery holds 50-90 Wh; a smartphone battery holds 10-15 Wh; an AA alkaline cell stores ~3 Wh. LED lamps labelled 9 W save 51 Wh/h over a 60 W incandescent. IATA dangerous-goods rules use Wh as the threshold for lithium batteries in aircraft: cells >20 Wh and batteries >100 Wh need special approval. 1 Wh = 3,600 J = 3.412 BTU.
Quick Reference Table
| Attojoules (aJ) | Watt-Hours (Wh) |
|---|---|
| 1 aJ | 2.778 × 10-22 Wh |
| 2 aJ | 5.556 × 10-22 Wh |
| 5 aJ | 1.389 × 10-21 Wh |
| 10 aJ | 2.778 × 10-21 Wh |
| 25 aJ | 6.944 × 10-21 Wh |
| 50 aJ | 1.389 × 10-20 Wh |
| 100 aJ | 2.778 × 10-20 Wh |