If the maximum value of accelerating potential provided by a radio frequency oscillator is 12 kV. The number of revolution made by a proton in a cyclotron to achieve one sixth of the speed of light is:
$[\mathrm{m_p} = 1.67 \times 10^{-27}\text{ kg},\ e = 1.6 \times 10^{-19}\text{ C},\ \text{Speed of light} = 3 \times 10^8\text{ m s}^{-1}]$