Always the perennial third in the national ratings, ABC News president Roone Arledge reformatted the program, relaunching it as World News Tonight on July 10, 1978. Reynolds, who was demoted when the network hired Reasoner, returned as lead anchor, reporting from ABC News' Washington, D.C. bureau.
The correct unit for measuring energy capacity of a battery product is called watt-hours. Watt-hours signifies that a battery can supply an amount of watts for an hour. For example, a 60 watt-hour battery can power a 60 watt light bulb for an hour. The same battery would run a 5W phone for 12 hours and power a 1W LED light bulb for 60 hours.
This is where the Watt hours come in play. If a battery is rated 20 Watt hours, it will mean that it will last for 20 hours if 1 Watt power is drawn from it. Now watt is defined at the product of the Volt ( at the battery) and Ampere ( drawn from the battery). In the previous example, the 20 Ampere Hour 7.2 Volt battery would be rated as 1440 Watt Hour while the 20 Ampere Hour 3.6 Volt battery would be rated at 720 Watt Hour. You can use the battery life calculator to calculate the life of a battery.