A Hall Voltage Is Measured to Be 15 $\mu$ V Across the 3

Multiple Choice

A Hall voltage is measured to be 15 $\mu$ V across the 3.0-mm dimension of a slab of copper whose overall dimensions are 2.0 * 3.0 *25.4 mm. The current passing through the copper is 20.0 A, while the magnetic field is 0.010 T. The density of the charge carriers in the material is

A) 3.3 *10²⁴ m^-3.
B) 2.8 *10²⁵ m^-3.
C) 4.2* 10²⁵ m^-3.