In a certain region of space, the electric field is zero. from this fact, what can you conclude about the electric potential in this region?

Occurs when an energy source transfers heat directly to another subject space; an example would be an object becoming warm by sitting in the sunshine

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.

Can anybody me with this? ? (picture included.)