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Saturday, 31 October

JEE Main 2023 · PhysicsNumerical answerNumerical valueMediumMulti-step

JEE Main 10 April 2023, Shift 2, Physics Q55

Question 55 of 90 in this shift, Physics question 25 of 30, Section B.

An electron revolves around an infinite cylindrical wire having uniform linear charge density 2×10−82\times10^{-8} C m−1^{-1} in circular path under the influence of attractive electrostatic field as shown in the figure. The velocity of electron with which it is revolving is ________ ×106\times10^6 m s−1^{-1}. Given mass of electron = 9×10−319\times10^{-31} kg

The figure, in words

Vertical wire marked with + signs along its length (a '-' sign at the top end) with an electron (e-) moving on a horizontal circular path around the wire.

Official answer

8

NTA final key.

Chapter
Electric Charges and Fields
Topic
Gauss's Law
Idea tested
Cylindrical Field

Same idea in other shifts

Asked 5× in all
  1. 4 Apr 2024, Shift 1 · Q40An infinitely long positively charged straight thread has a linear charge density λ\lambda Cm−1^{-1}. An electron revolves along a…HardDiagram basedHas a figure
  2. 30 Jan 2024, Shift 2 · Q40A particle of charge '−q-q' and mass 'mm' moves in a circle of radius 'rr' around an infinitely long line charge of linear charge…MediumSingle correct
  3. 27 Jul 2022, Shift 1 · Q56A long cylindrical volume contains a uniformly distributed charge of density ρ\rho Cm−3^{-3}. The electric field inside the cylindrical…EasyNumerical valueHas a figure
  4. 24 Jun 2022, Shift 2 · Q46A long cylindrical volume contains a uniformly distributed charge of density ρ\rho. The radius of cylindrical volume is RR. A charge…MediumSingle 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. 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.