A uniformly charged ring of radius `R` is rotated about its axis with constant linear speed `v` of each of its particle. The ratio of electric field to magnetic field at a point `P` on the axis of the ring distant `x=R` from centre of ring is `( c` is speed of light )

Options

A. `(c^(2))/(v)`
B. `(v^(2))/( c)`
C. `(v)/(c )`
D. `(c )/ (v)`

Answer

A

Explanation

At point P,
`E=(1)/(4piepsilon_(0)).(qx)/((R^(2)+x^(2))^(3//2))`
`B=(mu_(0))/(4pi).(2iA)/((R^(2)+x^(2))^(3//2))`
Hence, `i=(q)/(T)=(q upsilon)/(2piR)` and `A=piR^(2)`
`:." "(E)/(B)=(1)/(mu_(0)epsilon_(0)).(1)/(upsilon)=(c^(2))/(upsilon)`
`[c=(1)/(mu_(0)epsilon_(0))]`