Voltage breakdown in air at standard temperature and pressure occurs at an electric field strength of approximately 3 × 10⁶ V/m. This becomes an issue in some high-power optical experiments, in which tight focusing of light may be necessary. Estimate the light-wave power in watts that can be focused into a cylindrical beam of 10μm radius before breakdown occurs. Assume uniform plane wave behavior (although this assumption will produce an answer that is higher than the actual number by as much as a factor of 2, depending on the actual beam shape).