Question

calculate the potential difference between the plates of a parallel plate capacitor so that the gravitational force on a proton would be balanced by the electric field(proton mass = 1.67 x 10^-27kg, plate separation 0.5cm)

Answer 1

For the two force to be balanced: \[qE=mg\\E=\frac{mg}{q}\\V=Ed\\V= \frac{mgd}{q}\]