Charge q is uniformly spread on a thin ring of radius R . The ring rotates about its axis with a uniform frequency f Hz. The magnitude of magnetic induction at the centre of the ring is

Question

Charge q is uniformly spread on a thin ring of radius R . The ring rotates about its axis with a uniform frequency f Hz. The magnitude of magnetic induction at the centre of the ring is (A) (μ0 q f/2R) (B) (μ0 q/2fR) (C) (μ0 q/2π f R) (D) (μ0 q f/2 π R)

Tardigrade Admin · Accepted Answer

We know magnetic field β = (μ0i/2R) q = it ⇒ i = (q/t) = q f ∴ β = (μ0 q f/2R)

Q. Charge $q$ is uniformly spread on a thin ring of radius $R$ . The ring rotates about its axis with a uniform frequency $f Hz$ . The magnitude of magnetic induction at the centre of the ring is

$\frac{μ _{0} q f}{2 R}$

$\frac{μ _{0} q}{2 f R}$

$\frac{μ _{0} q}{2 π f R}$

$\frac{μ _{0} q f}{2 π R}$

We know magnetic field
$β = \frac{μ _{0} i}{2 R}$
$q =$ it
$\Rightarrow i = \frac{q}{t} = q f$
$∴ β = \frac{μ _{0} q f}{2 R}$

Q. Charge q is uniformly spread on a thin ring of radius R . The ring rotates about its axis with a uniform frequency fHz. The magnitude of magnetic induction at the centre of the ring is

2Rμ0​qf​

2fRμ0​q​

2πfRμ0​q​

2πRμ0​qf​