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JEE Main 202131 AugustEvening Shift
Exam
JEE Main
Year
2021
Date
31 August
Shift
Evening Shift
Subject
Physics
Chapter
Magnetic Effects of Current

JEE Main 2021 · 31 August · Evening Shift · Physics · Magnetic Effects of Current

A current of 1 . 5A is flowing through a triangle, of side 9cm...

A current of 1.5A1 . 5A is flowing through a triangle, of side 9cm9cm each. The magnetic field at the centroid of the triangle is :
(Assume that the current is flowing in the clockwise direction.)A current of 1 . 5A is flowing through a triangle, of side 9cm each. The magnetic field at the centroid of the triangle

Options

  1. A23×10−5T,2\sqrt{3} \times {10}^{- 5}T, inside the plane of triangle
  2. B23×10−7T,2\sqrt{3} \times {10}^{- 7}T, outside the plane of triangle
  3. C3×10−7T,3 \times {10}^{- 7}T, outside the plane of triangle
  4. D3×10−5T,3 \times {10}^{- 5}T, inside the plane of triangle

Correct answer

D. 3×10−5T,3 \times {10}^{- 5}T, inside the plane of triangle

Step-by-step solution

A current of 1 . 5A is flowing through a triangle, of side 9cm each. The magnetic field at the centroid of the triangle
B1=μ0I4\piR(2sin⁡60)=4π×10−7×1.54π.(332)×10−2×2×32=1×10−5{B}_{1} = \dfrac{{\mu}_{0}I}{4\piR}\left(2\sin 60\right) = \dfrac{4\pi \times {10}^{- 7} \times 1 . 5}{4\pi . \left(\dfrac{3\sqrt{3}}{2}\right) \times {10}^{- 2}} \times 2 \times \dfrac{\sqrt{3}}{2} = 1 \times {10}^{- 5}
Bnet=3B1=3×10−5T⊗{B}_{net} = 3{B}_{1} = 3 \times {10}^{- 5}T ⊗
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