Watt-hours to Megaelectronvolts (Wh to MeV)

1 watt-hour equals 2.246943267×10¹⁶ megaelectronvolts (rounded).

1 watt-hour = 2.246943267×10¹⁶ megaelectronvolts

How to convert watt-hours to megaelectronvolts

To convert watt-hours to megaelectronvolts, multiply the number of watt-hours by 2.246943267×10¹⁶. The factor is rounded to 10 significant digits. To go the other way, multiply megaelectronvolts by 4.45049065×10⁻¹⁷.

megaelectronvolts = watt-hours × 2.246943267×10¹⁶

Example: 10 watt-hours = 2.246943267×10¹⁷ megaelectronvolts.

The 'calorie' on food labels is really a kilocalorie. The thermochemical calorie (4.184 J) is used here unless marked IT.

About these units

Watt-hour (Wh)

Metric (SI)Current unit

Exactly 3,600 joules, the energy used by a one-watt device in an hour. Battery capacities are quoted in watt-hours.

Pair a power unit with a unit of time and you get the watt-hour: one watt sustained for one hour, which works out to 3,600 joules. The watt itself was adopted at the second International Electrical Congress in 1889, in the same session that adopted the joule, so the two units share a birthday even though the watt-hour is the one people read off batteries.

Battery capacity is where it earns its keep. Multiplying amp-hours by the battery voltage gives an estimate of watt-hours, so a 2,500 mAh lithium-ion cell at 3.7 V holds roughly 9.25 Wh. That is why a 500 mA USB device runs about 3.7 hours on it rather than five: the cell voltage, not the 5 V from the port, sets the energy.

For scale, an alkaline AA battery holds about 9 kJ, which is 2.5 Wh. A 12 W LED lamp left on for an hour uses 12 Wh, and a 40 W appliance running for 25 hours uses 1,000 Wh.

1 watt-hour = 3,600 joules (exactly).

Sources: Wikipedia: Watt-hour; Wikipedia: Joule; Wikipedia: Orders of magnitude (energy)

Megaelectronvolt (MeV)

ScientificCurrent unit

One million electronvolts. The scale of nuclear reactions.

Nuclei trade energy in millions of electronvolts. In binding-energy tables, medium-mass nuclei hold about 8.8 MeV per nucleon, with iron-56 listed at 8.7906 MeV. Fusing deuterium with tritium releases about 17.53 MeV per reaction, while an electron and positron annihilating give 1.022 MeV. One megaelectronvolt equals 1.602176634 x 10^-13 J, so even these reactions involve only tiny amounts of energy per event.

Per atom, though, the scale is enormous. A 17.53 MeV reaction is more than a million times the 1 to 10 eV that binds atoms into molecules, which is why nuclear fuels hold so much more energy than chemical ones. The electron's rest energy is 0.511 MeV and the muon's is 105.7 MeV, so the unit also serves for particle masses. A thousand MeV make one GeV, the next step up.

1 megaelectronvolt = 1.602176634×10⁻¹³ joules (exactly).

Sources: Wikipedia: Nuclear binding energy; Wikipedia: Electronvolt

Related conversions

See all energy units.