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Saturday, 31 October

JEE Main 2022 · PhysicsMultiple choiceSingle correctEasyApplication

JEE Main 27 June 2022, Shift 2, Physics Q42

Question 42 of 90 in this shift, Physics question 12 of 30, Section A.

Three identical charged balls each of charge 2 C are suspended from a common point P by silk threads of 2 m each (as shown in figure). They form an equilateral triangle of side 1m. The ratio of net force on a charged ball to the force between any two charged balls will be :

The figure, in words

Point P on a hatched ceiling line at the top; three threads each labelled 2m run from P down to balls B1 (lower left), B3 (middle, directly below P) and B2 (lower right). B1 and B2 are joined by a solid line labelled 1m; dashed lines labelled 1m join B3 to B1 and B3 to B2.
  1. (1)1:1
  2. (2)1:4
  3. (3)3\sqrt{3}:2
  4. (4)3\sqrt{3}:1Official answer

Official answer

Option 4

NTA final key.

Chapter
Electric Charges and Fields
Topic
Coulomb's Law
Idea tested
Superposition of Forces

Same idea in other shifts

Asked 5× in all
  1. 13 Apr 2023, Shift 2 · Q55Three point charges q, −2q-2q and 2q2q are placed on x-axis at a distance x=0x=0, x=34Rx=\frac{3}{4}R and x=Rx=R respectively from origin as…MediumNumerical valueHas a figure
  2. 26 Jul 2022, Shift 2 · Q57Three point charges of magnitude 5μC5\mu C, 0.16μC0.16\mu C and 0.3μC0.3\mu C are located at the vertices AA, BB, CC of a right angled triangle…MediumNumerical value
  3. 29 Jun 2022, Shift 2 · Q33Two point charges QQ each are placed at a distance dd apart. A third point charge qq is placed at a distance xx from mid-point on the…MediumSingle correct
  4. 18 Mar 2021, Shift 2 · Q22An infinite number of point charges, each carrying 1 μ\muC charge, are placed along the yy-axis at y=1y=1 m, 2 m, 4 m, 8 m…MediumNumerical value

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.