Question

About 40,000 J of energy is stored in a typical 1.5-V D-cell battery. If two such batteries are joined to produce a total of 3.0 V in a flashlight circuit and cause 2.0 A of current to flow through the flashlight bulb, how long will the batteries be able to deliver power to the flashlight at this level?

URGENT PLS HELP

Answer 1

Time = 13333.33 s = 222.22 min = 3.7 h

Step-by-step explanation:

The total amount of energy in two cells combined will be:

`Total\ Energy = 40000\ J + 40000\ J\\Total\ Energy = 80000\ J\\`

Now, we calculate the power of the batteries:

`Power = (Voltage)(Current)\\Power = (3\ V)(2\ A)\\Power = 6\ Watt`

Now, we use the following formula to calculate the time the batteries will be able to deliver the power to the flashlight:

`Total\ Energy = (Power)(Time)\\\\Time = (Total\ Energy)/(Power)\\\\Time = (80000\ J)/(6\ Watt)`

Time = 13333.33 s = 222.22 min = 3.7 h