The resistance of a copper wire 200 m long is 21 Q. If its thickness (diameter) is 0.44 mm, its specific resistance is around_______________?
A. 1.2 x 10~8 Q-m
B. 1.4 x 10~8 Q-m
C. 1.6 x 10″”8 Q-m
D. 1.8 x 10″8 Q-m
The resistance of a copper wire 200 m long is 21 Q. If its thickness (diameter) is 0.44 mm, its specific resistance is around_______________?