6. An ion is released from rest and moves due to the force from an electric field only. It starts from a position with a potential of 14 V to a position having a potential of 20 V. The ion: a. Must have a positive charge. b. Must have a negative charge. C. Can have either a positive or negative charge. d. Must be neutral. e. This whole statement is impossible! That can't happen.

The electric field strength between two parallel conducting plates separated by 4.00 cm is 7.50 104 V/m. (a) What is the potential difference between the plates? (b) The plate with the lowest potential is taken to be at zero volts. What is the potential 1.00 cm from that plate (and 3.00 cm from the other)?

What is the potential 0.530 x 10-10 m from a proton (the average distance between the proton and electron in a hydrogen atom)?

(a) Find the potential difference VB required to stop an electron (called a slopping potential) moving with an initial speed of 2.85 107 m/s. (b) Would a proton traveling at the same speed require a greater or lesser magnitude potential difference? Explain. (c) Find a symbolic expression for the ratio of the proton stopping potential and the electron stopping potential, Vp/Ve. The answer should be in terms of the proton mass mp and electron mass me.

The two charges in Figure P25.14 are separated by d = 2.00 cm. Find the electric potential at (a) point .A and (b) point B, which is halfway between the charges.

A 0.500-cm-diameter plastic sphere, used in a static electricity demonstration, has a uniformly distributed 40.0-pC charge on its surface. What is tire potential near its surface?

(a) Find the electric potential difference Ve required to stop an electron (called a stopping potential) moving with an initial speed of 2.85 107 m/s. (b) Would a proton traveling at the same speed require a greater or lesser magnitude of electric potential difference? Explain. (c) Find a symbolic expression for the ratio of the proton stopping potential and the electron stopping potential. Vp/Ve.

A particle with charge -40.0 nC is on the x axis at the point with coordinate x = 0. A second panicle, with charge -20.0 nC, is on the x axis at x = 0.500 in. (i) Is the point at a finite distance where the electric field is zero (a) to the left of .v = 0, (b) between x = 0 and x = 0.500 in, or (c) to the right of x m 0.500 in? (ii) Is the electric potential zero at this point? (a) No; it is positive, (b) Yes. (c) No; it is negative. (iii) Is there a point at a finite distance where the electric potential is zero? (a) Yes; it is to the left of x = 0. (b) Yes; it is between x = 0 and x = 0.500 in. (c) Yes; it is to the right of x = 0.500 in. (d) No.

Your friend gets really excited by the idea of making a lightning rod or maybe just a sparking toy by connecting two spheres as shown in Figure 7.39, and making R2so small that the electric field is greater than the dielectric strength of air, just from the usual 150 V/m electric field near the surface of the Earth. If R1is 10 cm. how small does R2to be, and does this seem practical? (Hint: recall the calculation for electric field at the surface of a conductor from Gauss's Law.)

In different experimental trials, an electron, a proton, or a doubly charged oxygen atom (O--), is fired within a vacuum tube. The particle's trajectory carries it through a point where the electric potential is 40.0 V and then through a point at a different potential. Rank each of the following cases according to the change in kinetic energy of the particle over this part of its flight from the largest increase to the largest decrease in kinetic energy. In your ranking, display any cases of equality, (a) An electron moves from 40.0 V to 60.0 V. (b) An electron moves front 40.0 V to 20.0 V. (c) A proton moves from 40.0 V to 20.0 V'. (d) A proton moves from 40.0 V to 10.0 V. (e) An O-- ion mines from 40.0 V to 60.0 V.