JEE Advanced · Physics · 22. AC Circuits
Paragraph :
The capacitor of capacitance \(C\) can be charged (with the help of a resistance \(R\) ) by a voltage source \(V\), by closing switch \(S_1\) while keeping switch \(S_2\) open. The capacitor can be connected in series with an inductor \(L\) by closing switch \(S_2\) and opening \(S_1\).

Question :
Initially, the capacitor was uncharged. Now, switch \(S_1\) is closed and \(S_2\) is kept open. If time constant of this circuit is \(\tau\), then
- A after time interval \(\tau\), charge on the capacitor is \(C V / 2\)
- B after time interval \(2 \tau\), charge on the capacitor is \(C V /\left(1-e^{-2}\right)\)
- C the work done by the voltage source will be half on the heat dissipated when the capacitor is fully charged
- D after time interval \(2 \tau\), charge on the capacitor is \(C V\left(1-e^{-1}\right)\)
Answer & Solution
Correct Answer
(B) after time interval \(2 \tau\), charge on the capacitor is \(C V /\left(1-e^{-2}\right)\)
Step-by-step Solution
Detailed explanation
Charge on capacitor at time \(t\) is \(q=q_0\left(1-e^{-t / \tau}\right)\)
\(\begin{array}{ll}\text { Here, } & q_0=C V \text { and } t=2 \tau \\ \therefore & q=C V\left(1-e^{-2 \tau / \tau}\right)=C V\left(1-e^{-2}\right)\end{array}\)
\(\begin{array}{ll}\text { Here, } & q_0=C V \text { and } t=2 \tau \\ \therefore & q=C V\left(1-e^{-2 \tau / \tau}\right)=C V\left(1-e^{-2}\right)\end{array}\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- Two batteries of different emfs and different internal resistances are connected as shown. The voltage across \(A B\) in volt is
JEE Advanced 2011 Easy - Two thin circular discs of mass m and 4m, having radii of a and 2a, respectively, are rigidly fixed by a massless, right rod of length through their center. This assembly is laid on a firm and flat surface, and set rolling without slipping on the surface so that the angular speed about the axis of the rod is . The angular momentum of the entire assembly about the point 'O' is (see the figure). Which of the following statement(s) is(are) true?
JEE Advanced 2016 Hard - A cylindrical furnace has height and diameter both . It is maintained at temperature . The air gets heated inside the furnace at constant pressure and its temperature becomes . The hot air with density rises up a vertical chimney of diameter and height above the furnace and exits the chimney (see the figure). As a result, atmospheric air of density , pressure and temperature enters the furnace. Assume air as an ideal gas, neglect the variations in and inside the chimney and the furnace. Also ignore the viscous effects.
[Given: The acceleration due to gravity and ]
Considering the air flow to be streamline, the steady mass flow rate of air exiting the chimney is _____ .JEE Advanced 2023 Medium - Two rectangular blocks, having identical dimensions, can be arranged either in configuration or in configuration as shown in the figure. One of the blocks has thermal conductivity and the other . The temperature difference between the ends along the x-axis is the same in both the configurations. It takes to transport a certain amount of heat from the hot end to cold end in the configuration . The time to transport the same amount of heat in the configuration is
JEE Advanced 2013 Medium - The dimensions of a cone are measured using a scale with a least count of \(2 \mathrm{~mm}\). The diameter of the base and the height are both measured to be \(20.0 \mathrm{~cm}\). The maximum percentage error in the determination of the volume is _______ .JEE Advanced 2024 Easy
- When two identical batteries of internal resistance \(1 \Omega\) each are connected in series across a resistor \(R\), the rate of heat produced in \(R\) is \(J_1\). When the same batteries are connected in parallel across \(R\), the rate is \(J_2\). If \(J_1=2.25 J_2\) then the value of \(R\) in \(\Omega\) isJEE Advanced 2010 Medium
More PYQs from JEE Advanced
- Statement 1 The sensitivity of a moving coil galvanometer is increased by placing a suitable magnetic material as a core inside the coil.
and Statement 2 Soft iron has a high magnetic permeability and cannot be easily magnetized or demagnetized.JEE Advanced 2008 Easy - The density (in \(\mathrm{g} \mathrm{cm}^{-3}\) ) of the metal which forms a cubic close packed (ccp) lattice with an axial distance (edge length) equal to 400 pm is \(\qquad\) .
Use: Atomic mass of metal \(=105.6 \mathrm{amu}\) and Avogadro's constant \(=6 \times 10^{23} \mathrm{~mol}^{-1}\)JEE Advanced 2025 Medium - The correct statement(s) about and is (are)
[Atomic number of Cr = 24 and Mn = 25]JEE Advanced 2015 Easy - The correct order of acidity for the following compounds is :
JEE Advanced 2016 Medium - Let \(f\) be a real-valued differentiable function on \(R\) (the set of all real numbers) such that \(f(1)=1\). If the \(y\)-intercept of the tangent at any point \(P(x, y)\) on the curve \(y=f(x)\) is equal to the cube of the abscissa of \(P\), then the value of \(f(-3)\) is equal toJEE Advanced 2010 Medium
- of molal urea solution (density at ) is mixed with of a solution containing of urea. Both the solutions were prepared in the same solvent. The osmotic pressure (in torr) of the resulting at is
[Use : Molar mass of urea ; gas constant, ;
Assume,JEE Advanced 2023 Easy