HARD
JEE Main
IMPORTANT
Earn 100

At what value of the resistance Rx, in the circuit shown in the figure, will the total resistance between points A and B be independent of the number of cells?

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Important Questions on ELECTRODYNAMICS

HARD
JEE Main
IMPORTANT

Figure shows an infinite circuit formed by the repetition of the same link, consisting of resistances R1=4.0 Ω and R2=3.0 Ω. Find the resistance of this circuit between points Aand B.

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HARD
JEE Main
IMPORTANT

The gap between the plates of a parallel-plate capacitor is filled with glass of resistivity ρ=100  m. The capacitance of the capacitor equals C=4.0 nF. Find the leakage current of the capacitor, when a voltage V=2.0 kV is applied to it. (Permittivity of vacuum, ε0=0.885×10-11 F m-1ε= Dielectric constant for glass =6)

HARD
JEE Main
IMPORTANT
The gap between the plates of a parallel-plate capacitor is filled up with an inhomogeneous, poorly conducting medium, whose conductivity varies linearly in the direction perpendicular to the plates, from σ1=1.0 pS m-1 to σ2=2.0 pS m-1. Each plate has an area S=230 cm2 and the separation between the plates is d=2.0 mm. Find the current flowing through the capacitor due to a voltage V=300 V.
HARD
JEE Main
IMPORTANT
A long round conductor, of cross-sectional area S, is made of a material, whose resistivity depends only on the distance r from the axis of the conductor, as ρ=αr2, where α is a constant. Find,
(a) the resistance per unit length of such a conductor,
(b) the electric field strength in the conductor, due to which a current I flows through it.
HARD
JEE Main
IMPORTANT
A capacitor with capacitance C=400 pF is connected via a resistance R=650 Ω to a source of constant voltage V0. How soon will the voltage developed across the capacitor reach a value V=0.90V0? (ln10=2.3025)
HARD
JEE Main
IMPORTANT

A capacitor is filled with dielectric of permittivity, ε=2.1, loses half the charge acquired during a time interval, τ=3.0 min. Assuming the charge to leak only through the dielectric filler, calculate its resistivity (permittivity of vacuum, ε0=0.885×10-11 F m-1).

HARD
JEE Main
IMPORTANT

A circuit consists of a source of a constant emf ξ and a resistance R and a capacitor with capacitance C connected in series. The internal resistance of the source is negligible. At a moment t=0, the capacitance of the capacitor is abruptly decreased η-fold. Find the current flowing through the circuit as a function of time t.

HARD
JEE Main
IMPORTANT

An ammeter and a voltmeter are connected in series to a battery with an emf ξ=6.0 V. When a certain resistance is connected in parallel with the voltmeter, the readings of the latter decrease η=2.0 times, whereas the readings of the ammeter increase the same number of times. Find the voltmeter readings after the connection of the resistance.