Fig. 28-2 shows four different sets of wires that cross each other without actually touching. the magnitude of the current is the same in all four cases, and the directions of current flow are as indicated. for which configuration will the magnetic field at the center of the square formed by the wires be equal to zero?

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)

Name two kinds of practical electric pumps.

Which of the following compounds would be primarily ionic? methane, ch4, ammonia nh3, calcium chloride, cacl2, or carbon dioxide, co2