it depends what kind flashlight you use, and the temperature has effection on it too.
duracell obv.
it take an duracell battery in a flashlight non-stop lasts exactly 15 hours
That's going to depend on how often, and for how long, the flashlight is turned on.
It's the other way around, the battery powers the flashlight. There's no set answer to that. It depends on the capacity of the battery and the power consumption of the flaslight.
Not if it's a regular duracell non rechargeable battery
there is alkaline in duracell and also zink
The amount of electricity a Duracell battery holds varies by type and size. For example, a standard AA alkaline Duracell battery typically has a capacity of about 2000 to 3000 milliamp-hours (mAh). In terms of energy, this translates to approximately 2.4 to 3.6 watt-hours (Wh) for a single AA battery. Other types, like 9V or rechargeable batteries, will have different capacities.
Duracell batteries are a brand of battery made by Duracell Inc. which is an American manufacturing company owned by Berkshire Hathaway.
Duracell batteries typically last longer than other battery brands.
Duracell
Duracell FTW
a Duracell size D