Question

The storage battery of a car has an emf of 12 V. If the internal resistance of the battery is 0.4 Ω, what is the maximum current that can be drawn from the battery?
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Answer 1

Answer:-

Emf of car battery is 12V and internal and resistance of the battery is 0.4 ohm .

so, the maximum current will be obtained when no external resistance is offered by with joining the two terminals.

I mean, R_{ext}=0

see daigram,

according to Kirchoff's law,

E - r × I - Rext × I = 0 ,

here I is the maximum current passing through battery.

I = E/(Rext + r)= 12/(0 + 0.4) = 30

Ahence maximum current = 30A

Answer 2

Answer:

emf of car battery is 12V and internal and resistance of the battery is 0.4 ohm .

so,

the maximum current will be obtained when no external resistance is offered by with joining the two terminals.

see daigram,

according to Kirchoff's law,

E - r × I - Rext × I = 0 ,

here I is the maximum current passing through battery.

I = E/(Rext + r)= 12/(0 + 0.4) = 30

A hence maximum current = 30A