What is electrical resistivity? In a series e | vedclass

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(B) Electrical resistivity is the resistance offered by a unit length and unit cross-sectional area of a material. It is a characteristic property of

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Due to change in resistance

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(B) Electrical resistivity is the resistance offered by a unit length and unit cross-sectional area of a material. It is a characteristic property of the material.According to the formula $R = \rho \frac{l}{A}$, where $R$ is resistance, $\rho$ is resistivity, $l$ is length, and $A$ is the cross-sectional area.When the length of the wire is doubled $(l' = 2l)$, the resistance becomes $R' = \rho \frac{2l}{A} = 2R$.Since the voltage $V$ remains constant in the circuit, according to Ohm's Law $(V = IR)$, the current $I$ is inversely proportional to resistance $(I = \frac{V}{R})$.Therefore, when the resistance is doubled, the current becomes half of its original value, i.e., $I' = \frac{V}{2R} = \frac{I}{2} = \frac{5}{2} = 2.5\, A$.

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?

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