3) a small, 30 gram pith ball carrying 3 nc of charge is dangling from an insulating string. another charged pith ball carrying an unknown amount of charge is brought close to the first ball, causing it to shift away. when everything is in equilibrium, the two balls are horizontally separated by distance of 4 cm, and the string is tilted about 16 degrees away from the vertical direction. how much charge is on the second ball?

The metric unit of electrical power is the watt volt ampere ohm

Some material consisting of a collection of microscopic objects is kept at a high temperature. a photon detector capable of detecting photon energies from infrared through ultraviolet observes photons emitted with energies of 0.3 ev, 0.5 ev, 0.8 ev, 2.0ev, 2.5ev, and 2.8ev. these are the only photon energies observed. (a) draw and label a possible energy-level diagram for one of the microscopic objects, which has four bound states. on the diagram, indicate the transitions corresponding to the emitted photons. explain briefly. (b) would a spring–mass model be a good model for these microscopic objects? why or why not? (c) the material is now cooled down to a very low temperature, and the photon detector stops detecting photon emissions. next, a beam of light with a continuous range of energies from infrared through ultraviolet shines on the material, and the photon detector observes the beam of light after it passes through the material. what photon energies in this beam of light are observed to be significantly reduced in intensity (“dark absorption lines”)? explain briefly.

What are the dimensions of the cross section that passes through the points a, f, g, and d?