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QJEEM20Ph6163: JEE Main 2020 Physics - Class 12 JEEM20Ph6163 Solution: A charged particle going around in a circle can be considered…

A charged particle going around in a circle can be considered to be a current loop. A particle of mass m carrying charge q is moving in a plane with speed v under the influence of magnetic field B→. The magnetic moment of this moving particle:

Multiple Choice Options

  • A mv2B→2B2
  • B -mv2B→2B2
  • C -mv2B→B2
  • D -mv2B→2πB2

Step-by-Step Verified Solution

JEE Main 2020 (Online) 6th September Evening Slot Physics - Magnetic Effect of Current Question 125 English Explanation
Magnetic dipole moment

M = iA

⇒ M = (qT)×πR2

= qπR2(2πrv) = qvR2

⇒ M = qv2×vmqB

As you can see from the figure, direction of magnetic moment(M) is opposite to magnetic field.

∴ M→=−mv22BB^

= −mv22B(B→B)

= −mv22B2B→

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