a. Wire B is four times longer than wire 4, and the two wires have the same volume. If both wires are made of the same substance and if the resistance of wire A is 19 Ohms, what is the resistance of wire B (in Ohms)? What do you think about their resistivity? b. Briefly discuss about the Ohm's law and microscopic views of conduction through a metal. Consider the electrical resistivity of a metal is 20 Anm and its charge density is 10.0 x 1028 /m3 find the average time of collisions between the electrons.