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A thin ring of 10 cm radius carries a un...

A thin ring of 10 cm radius carries a uniformly distributed charge. The ring rotates at a constant angular speed of `40pi "rad s"^(-1)` about its axis, perpendicular to its plane. If the magnetic field at its centre is `3.8xx10^(-9)T`, then the charge carried by the ring is close to `(mu_(0)=4pi xx10^(-7)N//A^(2))`

A

`7 xx 10^(-6)` C

B

`4 xx 10^(-6)` C

C

`2 xx 10^(-6)` C

D

`3 xx 10^(-5)` C

Text Solution

Verified by Experts

The correct Answer is:
D
`B = (mu_(0))/(4pi) (qv)/(r^2) ""sin theta implies B = 10^(-7) (q omega r)/(r^2)`
`q = (3.8 xx 10^(-4))/(4pi ) implies q = 3 xx 10^(-5) C`
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