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Physics - Current Electricity Question with Solution | TestHub

PhysicsCurrent ElectricityElectrical instrumentMedium2 minPYQ_2015

PhysicsMediumsingle choice

A potentiometer wire has length $4 m$ and resistance $8 Ω$ . The resistance that must be connected in series with the wire and an accumulator of e.m.f. $2V$ , so as to get a potential gradient $1 mV$ per cm on the wire is :NEET 2015 (Phase 1)

Options:

Answer:

Solution:

$\frac{d V}{d t} = \frac{1 m V}{c m}$
For a potentiometer $1 c m$ of wire has $1 m V$ of voltage
So,
$400 c m$ has $0.4 V .$
Given R must be connected in series
$Δ V = 0.4 = \frac{2}{8 + R} \times 8$
$8 + R = \frac{16}{0.4} = \frac{160}{4} = 40$
$\Rightarrow R = 32 Ω$

Stream:NEETSubject:PhysicsTopic:Current ElectricitySubtopic:Electrical instrument

⏱ 2mℹ️ Source: PYQ_2015

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