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Saturday, 31 October

JEE Main 2020 · PhysicsMultiple choiceSingle correctMediumApplication

JEE Main 9 January 2020, Shift 1, Physics Q11

Question 11 of 75 in this shift, Physics question 11 of 25, Section A.

An electric dipole of moment p⃗=(−i^−3j^+2k^)×10−29\vec{p} = (-\hat{i} - 3\hat{j} + 2\hat{k}) \times 10^{-29} C.m is at the origin (0, 0, 0). The electric field due to this dipole at r⃗=+i^+3j^+5k^\vec{r} = +\hat{i} + 3\hat{j} + 5\hat{k} (note that r⃗⋅p⃗=0\vec{r} \cdot \vec{p} = 0) is parallel to :
  1. (1)(−i^−3j^+2k^)(-\hat{i} - 3\hat{j} + 2\hat{k})
  2. (2)(+i^+3j^−2k^)(+\hat{i} + 3\hat{j} - 2\hat{k})Official answer
  3. (3)(−i^+3j^−2k^)(-\hat{i} + 3\hat{j} - 2\hat{k})
  4. (4)(+i^−3j^−2k^)(+\hat{i} - 3\hat{j} - 2\hat{k})

Official answer

Option 2

NTA final key (Jan 2020).

Chapter
Electric Charges and Fields
Topic
Electric Dipoles
Idea tested
Electric Field on Equatorial Line

Same idea in other shifts

Asked 3× in all
  1. 5 Apr 2024, Shift 2 · Q58The electric field at point p due to an electric dipole is E. The electric field at point R on equatorial line will be Ex\frac{E}{x}. The…MediumNumerical valueHas a figure
  2. 15 Apr 2023, Shift 1 · Q41The electric field due to a short electric dipole at a large distance (rr) from center of dipole on the equatorial plane varies with…EasySingle correct

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.