A positively charged particle (9.35pC) is suspended in equilibrium in an electric field between two horizontal parallel plates with opposite charges. Each one of the square plates has a charge of 5.5x10^-5C; and are separated by 6.25mm and their sides are 11cm long
what is the mass of the particle?
The Attempt at a Solution
first i divided the charge of the particle by the elemental charge
i got 58364544
then i multiplied this number by a protons mass
i got 9.764x10^-20
the book says the answer is 4.9x10^-4