The velocity selector in in a mass spectrometer consists of a uniform magnetic field oriented at 90 degrees to a uniform electric field so that a charge particle entering the region perpendicular to both fields will experience an electric force and a magnetic force that are oppositely directed. If the uniform magnetic field has a magnitude of 11.9 ~\text{mT}11.9 mT, then calculate the magnitude of the electric field that will cause a proton entering the velocity selector at 25.325.3 km/s to be undeflected. Give your answer in units of kV/m.