A wire is made of two sections with different diameters. Which of the following statements is (are)
Please justify your answer.
a) The current through the thicker section is smaller than the current through the thinner section.
b) The electric field in the thicker section is smaller than the electric field in the thinner section.
c) The resistivity in the thicker section is smaller than the resistivity in the thinner section.
d) The current density in the thicker section is smaller than the current density in the thinner section.