A capacitor is constructed from two conducting with a plate separation of d. The voltage between the plates is 31.2 volts and the electric field between the two plates is measured to be E = 2805 V/m.

What is the minimum amount of force needed to push an electron from the positive plate back to the negative plate?

F=eE=1.6•10⁻¹⁹•2805 = 4.5•10⁻¹⁶ N

To calculate the minimum amount of force needed to push an electron from the positive plate back to the negative plate of a capacitor, we need to consider the electric force acting on the electron.

The electric force (F) on an electron in an electric field (E) can be calculated using the formula:

F = q * E

where q is the charge of the electron. The charge of an electron is given as -1.6 x 10^-19 coulombs.

In this case, the electric field (E) between the two plates of the capacitor is given as 2805 V/m.

So, let's plug in the values:

F = (-1.6 x 10^-19 C) * (2805 V/m)

Now we can calculate the force needed:

F = -4.48 x 10^-17 N

Therefore, the minimum amount of force needed to push an electron from the positive plate back to the negative plate of the capacitor is -4.48 x 10^-17 Newtons. It should be noted that the negative sign indicates that the force is in the opposite direction of the electric field.