Index fossils serve to identify (A). How thick a given rock layer should be. (B). Specific layers of rocks anywhere.
(C). The composition of different rock layers. (D). The exact location of oceans that no longer exist.

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) =_