Peoples Physics Concepts

13.7. Internal Resistance http://www.ck12.org

We can plug this value into the equation given above to find the internal resistance.

V=Em f−Ir

r=

Em f−V

I

r=

5 V− 4 .5 V

1 .5 A

r=. 33 Ω

Now we can find find the power dissipated by the resistor

P=IV

P=I(Ir)

P=I^2 r

P= ( 1 .5 A)^2 ∗. 33 Ω

P=.75 W

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URL: http://www.ck12.org/flx/render/embeddedobject/319

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1. In the circuit shown here, the battery produces anemfof 1.5 V and has an internal resistance of 0. 5 Ω.

a. Find the total resistance of the external circuit.