25. Electric Potential

An electron moves from point A to point B. The potential difference between these two points is 100 V. What is 

a. the point of higher potential?
b. the work done on the electron?
c. the final speed of the electron if its initial speed is zero?

What work is needed to assemble an equilateral triangle of side length 5 cm, with a 5µC charge at each vertex?

(II) A + 25 μC point charge is placed 6.0 cm from an identical +25 μC point charge. How much work would be required by an external force to move a +0.15 μC test charge from a point midway between them to a point 1.0 cm closer to either of the charges?

In an older television tube (CRT), electrons are accelerated by thousands of volts through a vacuum. If such a television set is laid on its back, would electrons be able to move upward against the force of gravity? What potential difference, acting over a distance of 2.4 cm, would be needed to balance the downward force of gravity so that an electron would remain stationary? Assume that the electric field is uniform.

A parallel-plate capacitor with a 1.0 mm plate separation is charged to 75 V. With what kinetic energy, in eV, must a proton be launched from the negative plate if it is just barely able to reach the positive plate?