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Saturday, 31 October

JEE Main 2020 · PhysicsMultiple choiceDiagram basedHardDiagram reading

JEE Main 4 September 2020, Shift 1, Physics Q10

Question 10 of 75 in this shift, Physics question 10 of 25.

Two charged thin infinite plane sheets of uniform surface charge density σ+\sigma_+ and σ−\sigma_-, where ∣σ+∣>∣σ−∣|\sigma_+| > |\sigma_-|, intersect at right angle. Which of the following best represents the electric field lines for this system :

The figure, in words

Each option shows two perpendicular axes through a common centre, the horizontal one labelled σ+\sigma_+ (at its right end) and the vertical one labelled σ−\sigma_- (at its top end), with nested closed field lines carrying small arrowheads around the centre. Option 1: nested diamond (rhombus) shaped lines, taller than wide. Option 2: nested diamond shaped lines, wider than tall. Option 3: concentric circles. Option 4: concentric ellipses, wider than tall.
  1. (1)[figure: field-line diagram]Official answer
  2. (2)[figure: field-line diagram]
  3. (3)[figure: field-line diagram]
  4. (4)[figure: field-line diagram]

Official answer

Option 1

NTA final key (Sep 2020).

Chapter
Electric Charges and Fields
Topic
Electric Field
Idea tested
Field of an Infinite Non-Conducting Sheet

Same idea in other shifts

Asked 5× in all
  1. 2 Apr 2025, Shift 1 · Q34A small bob of mass 100 mg and charge +10 μC+10\ \mu\mathrm{C} is connected to an insulating string of length 1 m. It is brought near to an…MediumSingle correctHas a figure
  2. 4 Apr 2024, Shift 1 · Q55An infinite plane sheet of charge having uniform surface charge density +σs C/m2+\sigma_s\ \mathrm{C/m^2} is placed on xx-yy plane. Another…MediumNumerical value
  3. 29 Jan 2024, Shift 1 · Q55An electron is moving under the influence of the electric field of a uniformly charged infinite plane sheet S having surface charge…HardNumerical value
  4. 25 Jun 2022, Shift 1 · Q38In the figure, a very large plane sheet of positive charge is shown. P1P_1 and P2P_2 are two points at distance ll and 2l2l from the…EasyDiagram basedHas 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 108 of the 174 JEE Main shifts held from 2017 to 2026.