Answer:
a. xy
Explanation:
The Faraday's law of induction can be used to express the relationship between the electric field line integral and the magnetic flux rate change in a closed loop. In order to ensure that the relationship between the two variables is equivalent to zero, the integration should be conducted on the xy plane. The correct option is option a.
The resistance is 4 times the resistance of the first wire. the formula is R = p*l/A with p being resistivity, l length and A area. So if you double length and half area, which botv result in more resistance, you get p*2/0.5 or 4 (p can be abandoned because it is the same. We take standard length and area as 1)