EASY
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Calculate the ratio of current flowing through the battery at t=0 and t=. ( t=0 is the time of closing of the switch)

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Important Questions on Electrostatics

MEDIUM

For the given input voltage waveform Vin (t), the output voltage waveform V0(t), across the capacitor is correctly depicted by :

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HARD
An infinite line charge of uniform electric charge density λ lies along the axis of an electrically conducting infinite cylindrical shell of radius R. At time t = 0, the space inside the cylinder is filled with a material of permittivity ε and electrical conductivity σ . The electrical conduction in the material follows Ohm's law. Which one of the following graphs best describes the subsequent variation of the magnitude of current density j(t) at any point in the material?
HARD
Two identical capacitors A and B, charged to the same potential 5V are connected in two different circuits as shown below at time t=0. If the charge on capacitors A and B at time t=CR is QA and QB respectively, then (Here e is the base of natural logarithm)

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HARD

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A capacitor of capacitance C=1 μF is suddenly connected to a battery of 100 V through a resistance R=100 Ω. The time taken for the capacitor to be charged to get 50 V is:

(Take ln2=0.69)

MEDIUM
In an LCR circuit as shown below both switches are open initially. Now switch S 1 is closed, S 2 kept open. ( q is charge on the capacitor and τ = RC  is capacitive time constant). Which of the following statement is correct?
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EASY

What is the charge on the capacitor in the circuit shown below?

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MEDIUM
Determine the charge on the capacitor in the following circuit:
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EASY

As shown in the figure, in steady state, the charge stored in the capacitor is _____×10-6 C.

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MEDIUM

A blackbox (BB) which may contain a combination of electrical circuit elements (resistor, capacitor or inductor) is connected with other external circuit elements as shown below in the figure (a) . After the switch (S) is closed at time t=0 , the current I as a function of time t is shown in the figure b .

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From this we can infer that the black-box contains

MEDIUM

Consider the circuit shown in the figure below:

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All the resistors are identical. The charge stored in the capacitor, once it is fully charged, is

HARD
A capacitor is discharging through a resistor R. Consider in time t1, the energy stored in the capacitor reduces to half of its initial value and in time t2, the charge stored reduces to one eighth of its initial value. The ratio t1t2 will be
HARD

In the following circuit the switch Sis closed at t =0. The charge on the capacitor C1 as a function of time will be given by Ceq= C1C2C1+ C2

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MEDIUM

The circuit shown in the figure consists of a charged capacitor of capacity 3 μF and a charge of 30 μC. At time t=0, when the key is closed, the value of current flowing through the 5 MΩ resistor is x μA. The value of x to the nearest integer is

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EASY

An RC circuit as shown in the figure is driven by a AC source generating a square wave. The output wave pattern monitored by CRO would look close to :

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MEDIUM
A capacitor of 50μF is connected in a circuit as shown in figure. The charge on the upper plate of the capacitor is _________ μC.
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MEDIUM

The circuit shown has been connected for a long time. The voltage across the capacitor is, 

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MEDIUM
In the given circuit diagram, when the current reaches a steady-state in the circuit, the charge on the capacitor of capacitance C will be:
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MEDIUM
In the given circuits a and b, switches S1 and S2 are closed at t=0 and kept close for a long time. The variation of currents in the two circuits for t0 are shown in the options. (Figures are schematic and not drawn to scale.)
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MEDIUM
A 4 μF capacitor, a resistance of 2.5 is in series with 12 V battery. Find the time after which the potential difference across the capacitor is 3 times the potential difference across the resistor [Given ln2=0.693]
HARD
An electric bulb, a capacitor, a battery and a switch are all in series in a circuit. How does the intensity of light vary when the switch is turn on?