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Physics - Current Electricity Question with Solution | TestHub

PhysicsCurrent ElectricityEquivalent ResistanceEasy2 minPYQ_2020

PhysicsEasysingle choice

The resistance of a wire is $R Ω .$ The wire is stretched to double its length keeping volume constant. Now the resistance of the wire will become

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Answer:

Solution:

When wire is stretched to doubled its length, its resistance becomes four times

$R = \frac{ρ l}{A} \times \frac{l}{l} = \frac{ρ l^{2}}{V}$

$R \propto l^{2} so \frac{R_{1}}{R_{2}} = \frac{l_{1}^{2}}{l_{2}^{2}}$

$\frac{R}{R_{2}} = \frac{l^{2}}{{(l)}^{2}}$

$R_{2} = 4 R$

Stream:NTA_ABHYAS_NEETSubject:PhysicsTopic:Current ElectricitySubtopic:Equivalent Resistance

⏱ 2mℹ️ Source: PYQ_2020

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