The decay of 40K has a half of 1.3 × 10 9 years. The age of the earth is estimated at 4.6 × 10 9 years. The decay of 40K is a major heat source for the earth's interior. Relative to today, how much more heat was produced by 40K in the early Archaeon era or 3.9 × 10 9 years ago?

Electroplating is a way to coat a complex metal object with a very thin (and hence inexpensive) layer of a precious metal, such as silver or gold. in essence the metal object is made the cathode of an electrolytic cell in which the precious metal cations are dissolved in aqueous solution. suppose a current of 480.ma is passed through an electroplating cell with an aqueous solution of agno3 in the cathode compartment for 46.0 seconds. calculate the mass of pure silver deposited on a metal object made into the cathode of the cell. round your answer to 3 significant digits. also, be sure your answer contains a unit symbol. ×10μ

What will a positive and a negative charge do if they are separated from each other?

Suppose a wire with a current is pushed upward by a magnetic field. how would the wire move if the direction of the current reversed? explain your answer.