What is electrical resistivity? In a series electrical circuit comprising a resistor made up of a metallic wire, the ammeter reads $5\, A$. The reading of the ammeter decreases to half when the length of the wire is doubled. Why?
What is electrical resistivity? In a series electrical circuit comprising a resistor made up of a metallic wire, the ammeter reads $5\, A$. The reading of the ammeter decreases to half when the length of the wire is doubled. Why?
Use the formula $R=\rho \frac{l}{A}$. Also, $V = R I$ . $R$ is doubled while
$V$ remains unchanged. Hence current becomes $\frac {I}{2}$.
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