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PhysicsCurrent ElectricityEquivalent ResistanceHard2 minPYQ_2020
PhysicsHardmultiple choice

Shown in the figure is a semicircular metallic strip that has thickness t and resistivity ρ. Its inner radius is R1 and outer radius is R2. If a voltage V0 is applied between its two ends, a current I flows in it. In addition, it is observed that a transverse voltage ΔV develops between its inner and outer surfaces due to purely kinetic effects of moving electrons (ignore any role of the magnetic field due to the current). Then (figure is schematic and not drawn to scale)

Question diagram: Shown in the figure is a semicircular metallic strip that ha

Options:(select one or more)

Answer:
A, C, D
Solution:

Resistance of the strip =ρπrtdr

R=net resistance

1R=tdrρπrtπρR1R2drr

R=πρtlnR2R1

Hence, current i =V0R=V0tπρlnR2R1

for elementary dr,

di=V0ρπrtdr=V0tdrρπr

i=nAev

V0tdrρπr=ntdrev

eE=mv2r=mV02n22ρ2π2r2×1r

mv2r=mV02n22ρ2π2r2×1r

E1r3

E=k1r3

ΔV=Edr=kR1R2drr2V02

    i2

Stream:JEE_ADVSubject:PhysicsTopic:Current ElectricitySubtopic:Equivalent Resistance
2mℹ️ Source: PYQ_2020

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