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Friday, 9 October

JEE Main 2020 · PhysicsMultiple choiceSingle correctMediumApplication

JEE Main 9 January 2020, Shift 2, Physics Q12

Question 12 of 75 in this shift, Physics question 12 of 25, Section A.

Two identical capacitors A and B, charged to the same potential 5V are connected in two different circuits as shown below at time t=0t=0. If the charge on capacitors A and B at time t=CRt=CR is QAQ_A and QBQ_B respectively, then (Here ee is the base of natural logarithm)

The figure, in words

Two circuits, each a charged capacitor (A, B) in series with a resistor R and a diode. In circuit A the diode is oriented so that it blocks discharge; in circuit B the diode is reversed (conducting), so the capacitor discharges through R.
  1. (1)QA=VC, QB=CVQ_A = VC,\ Q_B = CV
  2. (2)QA=CV2, QB=VCeQ_A = \frac{CV}{2},\ Q_B = \frac{VC}{e}
  3. (3)QA=VCe, QB=CV2Q_A = \frac{VC}{e},\ Q_B = \frac{CV}{2}
  4. (4)QA=VC, QB=VCeQ_A = VC,\ Q_B = \frac{VC}{e}Official answer

Official answer

Option 4

NTA final key (Jan 2020).

Chapter
Electrostatic Potential and Capacitance
Topic
RC Circuits
Idea tested
RC Circuits with Ideal Diodes

Same topic in other shifts

All RC Circuits questions
  1. 5 Apr 2026, Shift 2 · Q37Under steady state condition the potential difference across the capacitor in the circuit is __________ V.MediumSingle correctHas a figure
  2. 18 Mar 2021, Shift 1 · Q26The circuit shown in the figure consists of a charged capacitor of capacity 3 μ\muF and a charge of 30 μ\muC. At time t=0t=0, when the…EasyNumerical valueHas a figure
  3. 2 Apr 2017 (offline) · Q16In the given circuit diagram when the current reaches steady state in the circuit, the charge on the capacitor of capacitance C will be :EasySingle correctHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.