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NEET

Exam: NEET
Subject: Physics
Chapter: Electromagnetic Induction

NEET · Physics · Electromagnetic Induction

A magnetic field B is confined to a region r a ≤ and points out of...

A magnetic field B is confined to a region r a ≤ and points out of the paper (the z-axis), r = 0 being the centre of the circular region. A charged ring (charge = Q) of radius b, b > a and mass m lies in the x-y plane with its centre at the origin. The ring is free to rotate and is at rest. The magnetic field is brought to zero in time ∆t. Find the angular velocity ω of the ring after the field vanishes.

Options

A $\omega =\frac{QB{{a}^{2}}}{m{{b}^{2}}}$
B $\omega =\frac{QB{{a}^{2}}}{2m{{b}^{2}}}$
C $\omega =\frac{QB{{a}^{2}}}{3m{{b}^{2}}}$
D $\omega =\frac{QB{{a}^{2}}}{4m{{b}^{2}}}$

Correct answer

B. $\omega =\frac{QB{{a}^{2}}}{2m{{b}^{2}}}$

Step-by-step solution

Correct Option is : (B)

\omega =\frac{QB{{a}^{2}}}{2m{{b}^{2}}}

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