Tuesday, October 25, 2011

How long can a battery power a flashlight?

A 1.5-V alkaline D battery can provide about 50000 J of electric energy. If a current of 1.5 A flows through two D batteries while they檙e in the circuit of a flashlight, how long will the batteries be able to provide power to the flashlight?How long can a battery power a flashlight?Two things you need to know to solve this problem:



1. By definition, Power = Energy / Time .



2. Also, if a battery is providing current I at potential V, then it is producing power P = IV.



Good luck.