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What is the value of the loss volt and internal resistance of the battery?

  • Thread starter looi76
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  • #1
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Homework Statement


When a current of [tex]2A[/tex] flows the p.d across a battery's terminal falls from [tex]12V[/tex] to [tex]9V[/tex].
(a) What is the value of the loss volt?
(b) What is the internal resistance of the battery?

Homework Equations


Lost Volt = Ir

The Attempt at a Solution


(a) [tex]12V - 9V = 3V[/tex]

[tex]R = \frac{V}{I} = \frac{3}{2} = 1.5[/tex]

[tex]Lost Volt = 3 \times 1.5 = 4.5[/tex]

Is this correct?

(b) Don't know which equation to use :confused:
 

Answers and Replies

  • #2
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your last 4.5 is wrong and no need. It is (lost volt)*(internal rezistance of battery) and meaningless.

Lost volt: 3V
R=1.5 ohm
 
  • #3
Redbelly98
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Homework Statement


When a current of [tex]2A[/tex] flows the p.d across a battery's terminal falls from [tex]12V[/tex] to [tex]9V[/tex].
(a) What is the value of the loss volt?
(b) What is the internal resistance of the battery?

Homework Equations


Lost Volt = Ir

The Attempt at a Solution


(a) [tex]12V - 9V = 3V[/tex]

[tex]R = \frac{V}{I} = \frac{3}{2} = 1.5[/tex]

[tex]Lost Volt = 3 \times 1.5 = 4.5[/tex]

Is this correct?

You can always check by using units in the calculation:
[tex]3V \times 1.5 \mbox{ohms} = 4.5 \ V\times \mbox{ohms} [/tex]

Since the units (V x ohms) are not Volts, this can't be right.

(b) Don't know which equation to use :confused:
R = V/I, you already did it without realizing it :smile:
 

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