If the speed of a charged particle moving perpendicular to a uniform magnetic field is doubled, its cyclotron frequency of revolution will:

1. The cyclotron frequency is $\nu_c = \dfrac{qB}{2\pi m}$. 2. This expression contains only charge, field, and mass. 3. It does not contain the speed $v$, so changing $v$ does not change $\nu_c$. 4. Hence doubling the speed leaves the frequency unchanged; only the radius doubles. _Source: NCERT Class 12 Physics Ch 4 "Moving Charges and Magnetism", p.139_