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Saturday, 31 October

JEE Main 2020 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 5 September 2020, Shift 1, Physics Q12

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

Two capacitors of capacitances C and 2C are charged to potential differences V and 2V, respectively. These are then connected in parallel in such a manner that the positive terminal of one is connected to the negative terminal of the other. The final energy of this configuration is :
  1. (1)zero
  2. (2)32CV2\frac{3}{2}CV^2Official answer
  3. (3)256CV2\frac{25}{6}CV^2
  4. (4)92CV2\frac{9}{2}CV^2

Official answer

Option 2

NTA final key (Sep 2020).

Chapter
Electrostatic Potential and Capacitance
Topic
Parallel Plate Capacitors
Idea tested
Charge Sharing and Heat Loss

Same idea in other shifts

Asked 12× in all
  1. 3 Apr 2025, Shift 2 · Q38Using a battery, a 100 pF capacitor is charged to 60 V and then the battery is removed. After that, a second uncharged capacitor is…EasySingle correct
  2. 1 Feb 2024, Shift 1 · Q40Two identical capacitors have same capacitance C. One of them is charged to the potential V and other to the potential 2V. The negative…MediumSingle correct
  3. 30 Jan 2024, Shift 1 · Q55A capacitor of capacitance C and potential V has energy E. It is connected to another capacitor of capacitance 2 C and potential 2 V. Then…MediumNumerical value
  4. 8 Apr 2023, Shift 2 · Q55A 600 pF capacitor is charged by 200 V supply. It is then disconnected from the supply and is connected to another uncharged 600 pF…MediumNumerical value
  5. 11 Apr 2023, Shift 1 · Q41A parallel plate capacitor of capacitance 2 F is charged to a potential V, The energy stored in the capacitor is E1E_1. The capacitor is…EasySingle correct
  6. 26 Jun 2022, Shift 1 · Q40Two capacitors having capacitance C1C_1 and C2C_2 respectively are connected as shown in figure. Initially, capacitor C1C_1 is charged to…EasyDiagram basedHas a figure
  7. 27 Jun 2022, Shift 1 · Q57A capacitor of capacitance 50 pF is charged by 100 V source. It is then connected to another uncharged identical capacitor. Electrostatic…EasyNumerical value
  8. 17 Mar 2021, Shift 2 · Q21A 2 μ\muF capacitor C1\mathrm{C_1} is first charged to a potential difference of 10 V using a battery. Then the battery is removed and…EasyNumerical valueHas 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. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.