The correct answer is: D. high impedance
A series reactor is a type of inductor that is used to block AC current. It does this by creating a magnetic field that opposes the flow of current. The impedance of a series reactor is proportional to its inductance, which is the measure of its opposition to AC current. Therefore, a series reactor should have a high impedance in order to be effective in blocking AC current.
Option A is incorrect because a series reactor should have a high impedance, not a low resistance. Resistance is the measure of a material’s opposition to the flow of current, regardless of frequency. Inductance, on the other hand, is the measure of a material’s opposition to the flow of AC current. Therefore, a series reactor should have a high inductance, which will result in a high impedance.
Option B is incorrect because a series reactor should have a high impedance, not a high resistance. Resistance is the measure of a material’s opposition to the flow of current, regardless of frequency. Inductance, on the other hand, is the measure of a material’s opposition to the flow of AC current. Therefore, a series reactor should have a high inductance, which will result in a high impedance.
Option C is incorrect because a series reactor should have a high impedance, not a low impedance. Impedance is the total opposition to the flow of current, and it is equal to the square root of the sum of the squares of the resistance and reactance. Reactance is the measure of a material’s opposition to the flow of AC current, and it is equal to 2ÏfL, where f is the frequency of the AC current and L is the inductance of the material. Therefore, a series reactor should have a high inductance, which will result in a high impedance.