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PhysicsCurrent ElectricityEquivalent ResistanceEasy2 minPYQ_2017

PhysicsEasysingle choice

A uniform wire of length $l$ and radius $r$ has a resistance of $100 Ω$ . It is recast into a wire of radius $\frac{r}{2}$ . The resistance of new wire will be-

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Answer:

Solution:

$R = ρ \frac{l}{A}$
$A l = V$
$R = \frac{ρ V}{A^{2}}$
$ρ \to$ constant
$V \to$ constant
$R \propto \frac{1}{A^{2}} \propto$ $\frac{1}{{(r^{2})}^{2}}$
$R \propto \frac{1}{r^{4}}$
$R_{2} = 16 R_{1} = 1600 Ω$

Stream:JEESubject:PhysicsTopic:Current ElectricitySubtopic:Equivalent Resistance

⏱ 2mℹ️ Source: PYQ_2017

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