What best describes a lens galaxya. a group if stars that serve as a quick reference to different parts of the skyb. several billion stars arranged in a disk shape that has uneven edgesc. millions of planets are arranged in the shape of a disc with spiraling armsd. billions of stars arranged in the circular pattern with a flattened core

In the circuit, the switch s has been open for a long time and r = 125 kohm. it is then suddenly closed. (a) determine the time constant before the switch is closed. s (b) determine the time constant after the switch is closed. _ s (c) let the switch be closed at t = 0. find the current in the switch as a function of time. (use t for time. express your answer in milliamps and seconds.) i(t) =_