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Friday, 9 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctHardMulti-step

JEE Main 3 August 2021, Shift 2, Physics Q13

Question 13 of 90 in this shift, Physics question 13 of 30, Section A.

A magnetic needle of length 12 cm, suspended at its middle point by a thread, stays at an angle of 45∘45^\circ with the horizontal. If the pole strength of the needle is 2.4 Am, what vertical force should be applied to an end so as to keep it in horizontal position ? The horizontal component of the earth's magnetic field is 20 μT20\ \mu T.
  1. (1)4.8×10−54.8\times10^{-5} N
  2. (2)2.4×10−52.4\times10^{-5} N
  3. (3)Zero
  4. (4)9.6×10−59.6\times10^{-5} NOfficial answer

Official answer

Option 4

NTA final key.

Chapter
Magnetism and Matter
Topic
No close match in our taxonomy
Idea tested
No close match in our taxonomy

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 42 of the 174 JEE Main shifts held from 2017 to 2026.