Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
Most Important Selected Qs for JEE AdvancedPhysicsCapacitance

Let C be the capacitance of a capacitor discharging through a resistor R . Suppose t₁ is the time taken for the energy stored in the capacitor to reduce to half its initial value and t₂ is the time taken for the charge to reduce to one-fourth its initial value. Then the ratio t₁ / t₂ will be

Options

  1. A1
  2. B1 2
  3. C1 4
  4. D2

Correct answer

C. 1 4

Step-by-step solution

U= 1 2 q^2 C = 1 2 C (q₀ e^ -t / T )^2= q₀^2 2 C e^ -2 t / T (where = CR )U=U₁ e^ -2 t₁ / 1 2 U₁=U₁ e^ -2 t₁ / ; 1 2 =e^ -2 t₁ / t₁= T 2 2 Now, q=q₀ e^ -t / T aligned & 1 4 q _ o = q _ o e ^ - t / 2 ~T & t ₂= T 4=2 T 2 & t ₁ t ₂ = 1 4 aligned

Practice Capacitance on Quantrex Academy →

More from Capacitance

Passage: A container of height 2 m, length 2 m and breadth 1 m is made of insulating vertical walls and two large area horizontal metal plates ( M₁ and M₂ ) which extend far beyond 2026A parallel plate capacitor is having separation between plates 0.885 mm. It has a capacitance of 1 , F when the space between the plates is filled with an insulating material of re 2026A sphere of capacitance 100 pF is charged to a potential of 100 V. Another identical uncharged metal sphere is brought in contact with the charged sphere, then the change in the to 2026From the circuit given below, the capacitance between terminals A and B shown in the circuit is ______ F. (take C₁=C₂=C₃=1 F and C₄=2 F.) 2026A parallel plate air capacitor is connected to a battery. The plates are pulled apart at uniform speed v . If x is the separation between the plates at any instant, then the time r 2026Consider a circuit consisting of a capacitor ( 20 F), resistor ( 100 ) and two identical diodes as shown in figure. The resistance of diode under forward biasing condition is 10 . 2026The dimensional formula of 1 2 ₀ E^2 ( ₀ = permittivity of vacuum and E = electric field) is M^a L^b T^c . The value of 2a - b + c = _______. 2026A parallel plate air capacitor has a capacitance C . When it is half filled as show in figure with a dielectric constant K = 5 , the percentage increase in the capacitance is _____ 2026 Full Capacitance list All Most Important Selected Qs for JEE Advanced PYQs