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What is the resistance of R2?

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tjjavid | Student, Undergraduate | (Level 1) Honors

Posted June 25, 2013 at 2:45 PM via web

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What is the resistance of R2?

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted June 25, 2013 at 4:48 PM (Answer #1)

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The circuit in the figure is that of a resistor R1 in parallel with a set of resistors R2 and R3 that are in series. Across the two there is an applied voltage of 60 V.

The current `I_(R2)` and `I_(R3)` is equal as the two are is series. As the voltage drop across R2 is 30 V, the voltage drop across R3 is also 30 V. Or R2 = R3.

The equivalent resistance R is given by `(1/R) = 1/(R1) + (1/(R2+R3))`

`60/2 = 30 = R = (1/(R1) + (1/(2*R2)))^-1`

As there is only equation and two variables R1 and R2, a unique value of R2 cannot be determined.

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