Wheatstone Bridge Experiment Sheet
Schematic of the Wheatstone Bridge
$R_1$  Resistance of left side of the string.
$R_2$  Resistance of right side of the string.
$R_3$  Resistance of the resistor box.
$R_x$  Unknown resitor.
The implementation of the above schematic is shown here:
Resistance of the wire is directly proporional to it's length,
$$
R_1 = \rho \frac{l_1}{S}, \qquad R_2 = \rho \frac{l_2}{S}
$$
Here $S$ is cross sectional area of the string, $\rho$ is resistivity of the string material, $l_1$ and $l_2$ are
lengths of right and left side of the strings respectively.
Resistance of unknown resistor could be obtained by following formula when bridge is balanced:
$$
R_x = \frac{R_2}{R_1} R_3 = \frac{l_2}{l_1} R_3
$$
Length of the ruler is $l = 35$cm.
Experiment sheet:
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$R_3$ [$\Omega $]

$l_1$ [cm]

$l_2 = l  l_1$ [cm]

$R_{x}$ [$\Omega $]

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