Answer:
option D
Step-by-step explanation:
given,
A conductor is carrying current = 2.0 A is 0.5 mm thick
Hall voltage = 4.5 x 10-6 V
uniform magnetic field = 1.2 T
density of the charge = n =?
hall voltage =



n = 6.67 × 10²⁷ charges/m
hence the correct answer is option D