What must the charge (sign and magnitude) of a particle of mass 1.47g be for it to remain stationary when placed in a downward-directed electric field of magnitude 690N/C ?
Use 9.81m/s2 for the magnitude of the acceleration due to gravity.
PART B
What is the magnitude of an electric field in which the electric force on a proton is equal in magnitude to its weight?
Use 1.67×10−27kg for the mass of a proton, 1.60×10−19C for the magnitude of the charge on an electron, and 9.81m/s2 for the magnitude of the acceleration due to gravity.