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NTA Abhyas 2020
Exam
NTA Abhyas
Year
2020
Subject
Physics
Chapter
Magnetic Properties of Matter

NTA Abhyas 2020 · Physics · Magnetic Properties of Matter

If the magnetic moment and the pole strength of a bar magnet are...

If the magnetic moment and the pole strength of a bar magnet are 3.6×10−3Am23.6 \times {10}^{- 3}Am^{2} and 120×10−3Am120 \times {10}^{- 3}Am, then its magnetic length is

Options

  1. A33 cm
  2. B0.30.3 cm
  3. C3.33.3 cm
  4. D3333 cm

Correct answer

A. 33 cm

Step-by-step solution

For a bar magnet, the magnetic moment is

M=polestrength×magneticlengthM = polestrength \times magneticlength

So the magnetic length will be

lmag=Mm{l}_{mag} = \dfrac{M}{m}

⇒lmag=3.6×10−3120×10−3=3×10−2m=3cm⇒ {l}_{mag} = \dfrac{3.6 \times {10}^{- 3}}{120 \times {10}^{- 3}} = 3 \times {10}^{- 2}m = 3cm

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