HARD
Earn 100

Derive the expression of current as a function of time during the charging of the capacitor in the RC circuit.

Important Questions on Electromagnetic Induction (HL)

MEDIUM
A capacitor of capacitance C is given a charge Q. At t=0, it is connected to an uncharged capacitor of equal capacitance through a resistance R. Find the charge on the second capacitor as a function of time.
HARD

Consider the four circuits shown in the figure, each consisting of a battery, a switch, a light bulb, a resistor and either a capacitor or an inductor. Assume the capacitor has a large capacitance and the inductor has a large inductance but no resistance. The light bulb has high efficiency and glows whenever electric current passes through it.

(i) Describe what the light bulb does in each of circuits (a) through (d) after the switch is closed.

(ii) Describe what the light bulb does in each of circuits (a) through (d) when the switch has been closed for a long time interval and when the switch is opened.

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MEDIUM

In the circuit shows a capacitor that is initially uncharged is being charged by a battery.

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Which of the following is a correct graph of the variation of the potential difference V across the plates with charge q on one of the capacitor plates?

HARD
A capacitance C charged to a potential difference V is discharged by connecting its plates through a resistance R¯. Find the heat dissipated in one time constant after the connections are made. Do this by calculating i2Rdt and also by finding the decrease in the energy stored in the capacitor.
HARD

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.

EASY
The equation for the discharge current at any instant of time of RC circuit is
MEDIUM
A parallel-plate capacitor is filled with a dielectric material having resistivity ρ and dielectric constant K. The capacitor is charged and disconnected from the charging source. The capacitor is slowly discharged through the dielectric. Show that the time constant of the discharge is independent of all geometrical parameters like the plate area or separation between the plates. Find this time constant.
EASY

The charge on each of the capacitors, 0.20 ms after the switch S is closed in figure is

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HARD
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

The capacitor is discharging through a resistor of resistance 2.5 .  What is the current through the resistor when the charge on one of the plates has been reduced to 8.0 nC? Here capacitor attached with 6 V Ideal voltmeter. And initial charge in capacitor Is 12 nC.

EASY
A capacitor of capacitance 8.0 μF is connected to a battery of emf 6.0 V connected through a resistance of 24 Ω. Find the current in the circuit a just after the connections are made and b one time constant after the connections are made.
HARD

Find how the voltage across the capacitor C varies with time t after the shorting of the switch Sw at the moment t=0.

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MEDIUM

The graph shows the variation with time t of the current I for a discharging capacitor.

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What is the time constant of this system?(in sec)

EASY

The switch is closed at t=0 when the capacitors are uncharged. Find the charge on the capacitor C1 as a function of time t.

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EASY

A capacitor of 4 μF is connected as shown in the circuit. The internal resistance of the battery is 0.5 Ω. The amount of charge on the capacitor plates will be

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EASY

Two capacitors of equal capacitance C1=C2 are as shown in the figure. Initially, while the switch is open (as shown) one of the capacitors is uncharged and the other carries charge Q0. The energy stored in the charged capacitor is U0. Sometime after the switch is closed, the capacitors C1 and C2 carry charges Q1 and Q2, respectively. The energies stored in the capacitors are U1 and U2 respectively. Which of the following expression is correct?

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MEDIUM

The magnitude of the charge in steady-state on either of the plates of condenser C in the adjoining circuit is 

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MEDIUM

What will the initial current be in the below the instant the switch is closed, and what will it be eventually a long time after the switch is closed? (answer in order)

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MEDIUM

The switch S is kept closed for a long time and is then opened at t=0. Find the current in the middle 10 Ω resistor at t=1.0 ms.

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