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A 1.4 v d-cell battery is rated at 15,000 ma⋅h. part a for how long could such a battery power a flashlight bulb rated at 1.1 w ?

User Krlmlr
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1 Answer

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The current through a 1.1 watts light bulb is given by the equation

P=U*I \rightarrow I=P/U
Thus
I=1.1/1.4=0.786 A
The capacity of the battery is

C=15000 mA*h =15 A*h
In words we say that if a current of 15 A is taken from it, it lasts for 1 hour.
If we take a current I=0.786 A the battery lasts a time of

t=C/I=15/0.786 =19.1 hours


User Nschmidt
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