Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NTA Abhyas JEE Main2020PhysicsElectrostaticsPractice

A certain series R-C circuit is formed using resistance R, a capacitor without dielectric having a capacitance C = 2 F and a battery of emf E = 3 V. The circuit is completed and it is allowed to attain the steady state. After this, at t = 0 half the thickness of the capacitor is filled with a dielectric constant k = 2 as shown in the figure. The system is again allowed to attain a steady state. What will be the heat

Options

  1. A3
  2. B5
  3. C2
  4. D6

Correct answer

A. 3

Step-by-step solution

Initial charge on capacitor = CE Initial potential energy of capacitor = CE 2 /2 Now, C = ε 0 A/d And new capacitance C ′ = ε 0 A d/2 , in series with = ε 0 K A d/2 ⇒ C ' = 2 ∈ 0 A d in series with 4 ∈ 0 A d = ε 0 A d 2 × 4 2 + 4 = 4 ε 0 A 3 d = 4 3 C ⇒ New charge = 4 3 CE New energy = 1 2 × 4 3 CE 2 = 2 3 CE 2 Now W battery = Δ H + Δ U ⇒ E 4 3 CE - CE = Δ H + 2 3 CE 2 - 1 2 CE 2 ⇒ Δ H = 1 6 CE 2 = 3

Practice Electrostatics on Quantrex Academy →

More from Electrostatics

Two charges Q₁ = q and Q₂ = mq are placed at the points P₁(a, b) and P₂(ma, mb) , respectively, in the XY plane, where a, b 0 and m 0, 1 . If V₁ is the potential at a point in the 2026Consider an electric dipole comprising two charges +q and -q each with mass m , separated by a fixed distance d and initially at rest with its dipole moment pointing along i . A un 2026Two point charges q₁=3 , C and q₂=-4 , C are placed at points (2 i +3 j +3 k ) and ( i + j + k ) respectively. Force on charge q₂ is ________ N. ( Take 1 4 ₀ = 9 10^9 SI Units ) 2026The electric potential as a function of x, y is given by V = 5(x^2 - y^2) V. The electric field at a point (2, 3) m is __________ V/m. 2026A thin half ring of radius 35 cm is uniformly charged with a total charge of Q coulomb. If the magnitude of the electric field at centre of the half ring is 100 V/m, then the value 2026A three coulomb charge moves from the point (0, -2, -5) to the point (5, 1, 2) in an electric field expressed as E = 2x i + 3y^2 j + 4 k N/C. The work done in moving the charge is 2026A particle of charge q and mass m is projected from origin with an initial velocity v = ( v₀ 2 x + v₀ 2 y ) . There exists a uniform magnetic field B = B₀ z and a space varying ele 2026A rigid dipole undergoes a simple harmonic motion about its centre in the presence of an electric field E ₁=E₀ x . If another electric field E ₂=2E₀( y + z ) is introduced to the s 2026 Full Electrostatics list All NTA Abhyas JEE Main PYQs