- #1
Martinet
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Homework Statement
Show that V across Resistor Rkohms is: (11R) / (3.96 + 4R) V
The circuit is a 5V cell in series with a 1.8k resistor. Following the 1.8k resistor are a 2.2k and Rk resistor in parallel with each other. The wires then rejoin and return to the cell.Current through the circuit has already been found as 5(2.2 + R) / (3.96 + 4R) mA
Homework Equations
I = V/R
The Attempt at a Solution
I = 5(2.2 + R) / (3.96 + 4R)
thus I through R
= 5(2.2 + R) / (3.96 + 4R) * (R / 2.2 + R) <= Current is divided proportionally to the strength of the resistor.
= 5R / (3.96 + 4R) <= Simplification.
V = IR
thus V across R
= (5R / 3.96 + 4R)) * R <= Voltage is equal to the divided current * the resistance, R.
= 5R^2 / (3.96 + 4R) <= Simplification.
I'm not quite sure where I'm going wrong. I have a funny feeling it might have something to do with voltage divider theory but I can't see how that would be incorporated. ANy help would be much appreciated.