Physics - Current Electricity Question with Solution | TestHub

PhysicsCurrent ElectricityEquivalent ResistanceMedium2 minPYQ_2016

PhysicsMediumsingle choice

The length of a given cylindrical wire is increased by $150%$ . Due to the consequent decrease in diameter the change in the resistance of the wire will be

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Solution:

If suppose initial length, $I_{1} = 100$ , then $I_{2} = 100 + 150 = 250$ $∵ \frac{R _{1}}{R _{2}} = (\frac{I _{1}}{I _{2}})^{2} = (\frac{100}{250})^{2}$ $\Rightarrow \frac{R _{1}}{R _{2}} = \frac{4}{25} \Rightarrow R_{2} = \frac{25}{4} R_{1}$ $\Rightarrow \frac{Δ R}{R} \times 100 = \frac{R _{2} - R _{1}}{R _{1}} \times 100 = \frac{\frac{25}{4} R _{1} - R _{1}}{R _{1}} \times 100 = 525%$

Stream:JIPMERSubject:PhysicsTopic:Current ElectricitySubtopic:Equivalent Resistance

⏱ 2mℹ️ Source: PYQ_2016

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