Exams › JEE Advanced › Physics
A circuit contains a 20 microF capacitor in series with an 8 ohm resistor (top branch), a 4 ohm resistor in a parallel branch, and a 40 V battery with a 4 ohm internal/series resistor. Consider the following statements about this RC circuit: (P) Time constant is 0.1 ms (Q) Charge on the capacitor as a function of time is 400(1 - e^(-10000t)) microC (R) Current through the 8 ohm resistor at t = 0.4 * 10⁻³ s is 0.27 A (S) Charge on the capacitor in steady state is 400 microC Which of the above statements are correct?
- Time constant is 0.1 ms
- Charge on the capacitor as a function of time is 400 (1-e⁻¹⁰⁰⁰⁰t) microC
- Current through 8 ohm resistor at t = 0.4 * 10⁻³ sec is 0.27A
- Charge on the capacitor in steady state is 400 microC
Correct answer: Charge on the capacitor in steady state is 400 microC
Solution
In steady state, capacitor is fully charged and no current flows through the 8-ohm + capacitor branch. The current in the circuit is 40/(4+4) = 5 A through the two 4-ohm resistors. Voltage across capacitor = voltage across parallel 4-ohm = 5*4 = 20 V (wait, circuit topology needs clarification). With the described topology, V_cap(steady) = 20 V, so Q = CV = 20*20*10⁻⁶ = 400 microC. Statement S is correct.
Related JEE Advanced Physics questions
- A particle with charge -q and mass m revolves in a circular path of radius r around an infinitely long charged wire with linear charge density +λ. What is the time period of its motion?
- What is the value of the electrostatic potential at point H?
- The electric potential V varies with distance x from a fixed point as follows: V = 5 V for 0 <= x < 10 m, then V decreases linearly from 5 V at x = 10 m to -10 V at x = 20 m. The electric field at x = 13 m is:
- Two capacitors are connected in a circuit with two batteries and a switch S. The system is in steady state with S open. When S is closed, which of the following statements correctly describes the energy exchange?
- In a capacitor bridge circuit, four capacitors C1, C2, C3, and C4 are connected in a bridge configuration with an EMF source E. Capacitor C1 is in the top-left arm, C2 in the top-right arm, C3 in the bottom-left arm, and C4 in the bottom-right arm. Points P and Q are the mid-points (junctions). Find the potential difference V_P - V_Q.
- An isolated charged spherical soap bubble of radius r has the pressure inside equal to atmospheric pressure outside. The surface tension of the soap solution is T. If the total charge on the bubble can be written as N*pi*r*sqrt(2*T/epsilon0), find the integer value of N.
⚔️ Practice JEE Advanced Physics free + battle 1v1 →