Question

What are the strength and direction of an electric field that will balance the weight of a proton and an electron

Answer 1

E = mg/e

elect----> E = (9.1e-31)*9.8/(1.6e-19) = 5.58e-11 N/C

prot--> E = (1.64e-27)*9.8/(1.6e-19)= 1.02e-7 N/C

Answer 2

The answers are
Proton:1.0x10^-7 N/C upward
and Electron: 5.6x10^-11 N/C downward
Use the formula E=force/charge. Weight of electron is 9.11x10^-31x9.81=8.93691x10^-30N and charge is 1.60x10^-19 C. Put then into the formula you will get 5.6x10^-11 N/C. Direction is downwards because the electric field goes from positive plate to negative plate so the top plate needs to be positive to balance out the weight since the electron would be attracted to the positive plate.
b)upward
d)downward

Answer 3

Use the formula E=force/charge. Weight of electron is 9.11x10^-31x9.81=8.93691x10^-30N and charge is 1.60x10^-19 C. Put then into the formula you will get 5.6x10^-11 N/C. Direction is downwards because the electric field goes from positive plate to negative plate so the top plate needs to be positive to balance out the weight since the electron would be attracted to the positive plate.