If you walk across a nylon rug and then touch a large metal object such as a doorknob, you may get a spark and a shock. Why does this tend to happen more on dry days than on humid days? Why are you less likely to get a shock if you touch a small metal object, such as a paper clip?

k3 8.99 x 10° Nm?/C?, me 3D 9.11 x 10-31 kg, e %3D 1.6 х 10-19 С, тр 3D 1.67 х 10-27 kg 1. Electrons start from rest and are accelerated east by two plates (parallel to the north/south directions) through a potential difference. They then pass into a second set of parallel plates 1.2 cm long (parallel to the east/west direction). When the electrons leave the second set of plates they are moving at 3.0 x 106 m/s [E 30º N]. You may ignore gravity. (For this question but not in the real world!) Find the potential difference across the first set of plates and the electric field between the second set of plates. 1.2 cm Path of electron First set of plates Second set of plates

Two metal spheres, each of radius 3.1 cm, have a center-to-center separation of 1.5 m. Sphere 1 has a charge of +1.3 × 10-8 C; sphere 2 has a charge of -2.7 x 10-8 C. Assume that the separation is large enough for us to assume that the charge on each sphere is uniformly distributed (the spheres do not affect each other). With V= 0 at infinity, calculate in volts (a) the potential at the point halfway between their centers and the potential on the surface of (b) sphere 1 and (c) sphere 2.

Identical 42 μC charges are fixed on an x axis at x = ±3.4 m. A particle of charge q = –20 μC is then released from rest at a point on the positive part of the y axis. Due to the symmetry of the situation, the particle moves along the y axis and has kinetic energy 1.2 J as it passes through the point x = 0, y = 4.5 m. (a) What is the kinetic energy of the particle as it passes through the origin? (b) At what negative value of y will the particle momentarily stop?