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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumApplication

JEE Main 31 August 2021, Shift 1, Physics Q12

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

Two particles A and B having charges 20 μ\muC and −5-5 μ\muC respectively are held fixed with a separation of 5 cm. At what position a third charged particle should be placed so that it does not experience a net electric force ?

The figure, in words

A horizontal line with point A (labelled 20 microC) on the left and point B (labelled -5 microC) on the right, separation 5 cm marked between them.
  1. (1)At midpoint between two charges
  2. (2)At 5 cm from −5-5 μ\muC on the right sideOfficial answer
  3. (3)At 5 cm from 20 μ\muC on the left side of system
  4. (4)At 1.25 cm from a −5-5 μ\muC between two charges

Official answer

Option 2

NTA final key.

Chapter
Electric Charges and Fields
Topic
Coulomb's Law
Idea tested
Null Point Location Calculation

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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.