Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
Concepts Of Physics MCQ Edition [Volume 2]PhysicsElectric Current in Conductors

At t = 0 , the plates of a capacitor of capacitance 10 ext F , charged to 60 ext C , are connected together by a wire having a resistance of 10 ext . Determine the charge on the capacitor in the circuit at t = 30 ext s .

Options

  1. A32 ext C
  2. B44 ext C
  3. C22 ext C
  4. D18 ext C

Correct answer

B. 44 ext C

Step-by-step solution

The time constant of the discharging RC circuit is given by = RC . Substituting the given values: = 10 10 10⁻⁶ s = 100 s The charge on the capacitor during discharging is given by: q = q₀ e^ -t/ Substituting q₀ = 60 C and t = 30 s : q = 60 e^ -30/100 = 60 e^ -0.3 C Using the approximation e^ -0.3 0.74 : q 60 0.74 C = 44.4 C The closest value among the given options is 44 C .

Practice Electric Current in Conductors on Quantrex Academy →

More from Electric Current in Conductors

The amount of charge passing through a cross-section of a wire in time t is given by Q(t) = At^2 + Bt + C . Determine the dimensional formulae for A , B , and C .A discharge tube carries an electric current of 2.0 A . Determine the amount of charge that passes through a cross-section of the tube in 5 minutes.The current flowing through a wire varies with time according to i = i₀ + t , where i₀ = 10 A and = 4 A s ⁻¹ . Determine the charge that crosses a section of the wire in 10 secondsA copper wire with a cross-section of 1.0 mm ^2 carries a current of 1.0 A . Determine the drift speed of the free electrons in the wire, assuming there is one free electron per atAn electron gun releases 2.0 10¹⁶ electrons per second. Determine the electric current this corresponds to.The amount of charge passing through a cross-section of a wire in time t is Q(t) = At^2 + Bt + C . Assuming the numerical values of A , B , and C in SI units are 5 , 3 , and 1 respA uniform wire having a resistance of 100 is melted and recast into a new wire whose length is double that of the original. What will be the resistance of the new wire?Determine the required length of a copper wire having a cross-sectional area of 0.01 mm ^2 to produce a resistance of 1 k . The resistivity of copper is given as 1.7 10⁻⁸ m . Full Electric Current in Conductors list All Concepts Of Physics MCQ Edition [Volume 2] PYQs