Two parallel horizontal plates are spaced 0.40 cm apart in air. you introduce an oil droplet of mass 4.9 × 10^–17 kg between the plates. if the droplet carries two electronic charges and if there were no air buoyancy, you could hold the droplet motionless between the plates if you kept the potential difference between them at a) 60 v b) 12 v c) 3.0 v d) 0.12 kv e) 6.0 v

Aparticle of mass m is placed in a one-dimensional box of length l. the box is so small that the particle’s motion is relativistic, so that e p2/2m is not valid. (a) derive an expression for the energy levels of the particle using the relativistic energy–momentum relation and the quantization of momentum that derives from connement. (b) if the particle is an electron in a box of length l 1.00 1012 m, nd its lowest possible kinetic energy. by what percent is the nonrelativistic formula for the energy in error?