Consider the bohr model of the doubly ionized lithium atom (lithium has z=3). (15 pts) a. what are the three lowest allowed energies e1, e2, and ez. of the electron (in ev)? b. what are the different energies of photons that can be emitted when the electron undergoes transitions from the third level eg to lower energy levels? c. which of the preceding transitions results in the longest wavelength photon?

Your physics assignment is to figure out a way to use electricity to launch a small 6.0-cm-long plastic drink stirrer. you decide that you'll charge the little plastic rod by rubbing it with fur, then hold it near a long, charged wire, as shown in figure p23.56 . when you let go, the electric force of the wire on the plastic rod will shoot it away. suppose you can uniformly charge the plastic stirrer to 10 nc and that the linear charge density of the long wire is 1.0 x10-7 c/m. what is the net electric force on the plastic stirrer if the end closest to the wire is 2.0 cm away?