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Saturday, 31 October

JEE Main 2020 · PhysicsMultiple choiceSingle correctMediumMulti-step

JEE Main 4 September 2020, Shift 2, Physics Q13

Question 13 of 75 in this shift, Physics question 13 of 25.

A circular coil has moment of inertia 0.8 kg m2^2 around any diameter and is carrying current to produce a magnetic moment of 20 Am2^2. The coil is kept initially in a vertical position and it can rotate freely around a horizontal diameter. When a uniform magnetic field of 4 T is applied along the vertical, it starts rotating around its horizontal diameter. The angular speed the coil acquires after rotating by 60∘^\circ will be :
  1. (1)20 rad s−1^{-1}
  2. (2)10 rad s−1^{-1}Official answer
  3. (3)20 π\pi rad s−1^{-1}
  4. (4)10 π\pi rad s−1^{-1}

Official answer

Option 2

NTA final key (Sep 2020).

Chapter
Moving Charges and Magnetism
Topic
Magnetic Dipole Moment
Idea tested
Kinetic Energy Gained in Rotation

Same topic in other shifts

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  6. 4 Apr 2024, Shift 1 · Q57The magnetic field existing in a region is given by B⃗=0.2 (1+2x)k^ T\vec{B} = 0.2\,(1 + 2x)\hat{k}\,\mathrm{T}. A square loop of edge 50 cm carrying 0.5…HardNumerical valueHas a figure

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.