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Physics - Current Electricity Question with Solution | TestHub

PhysicsCurrent ElectricityEquivalent ResistanceEasy2 minPYQ_2004

PhysicsEasysingle choice

The electric resistance of a certain wire of iron is $R$ . If its length and radius are both doubled, then:NEET 2004

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Solution:

Resistance of wire $R = ρ \frac{l}{A}$ Means $R \propto \frac{l}{A} = \frac{l}{π r ^{2}}$ According to the question when $l$ and $R$ are doubled $∴ R_{1} \propto \frac{2 l}{π ( 2 r ) ^{2}} \Rightarrow R_{1} \propto \frac{1}{2} R$ Here specific resistance of wire is independent of geometry wire so it depends on the material of wire.

Stream:NEETSubject:PhysicsTopic:Current ElectricitySubtopic:Equivalent Resistance

⏱ 2mℹ️ Source: PYQ_2004

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