The electron density in copper is 8.49 *10²⁸ electrons/m³.The electron charge is e = -1.60 *10 ^- ¹⁹ C.When a 1.00 A current is present in a copper wire with a 0.40 cm² cross-section,the electron drift velocity,in m/s,with direction defined relative to the current density,is A)-1.84 *10 ^- ⁶. B)+1.84 * 10 ^- ⁶. C)-1.84. D)-5.43 * 10 ^- . E)+5.43 * 10 ^- .

Question

Quizplus · Accepted Answer

The drift velocity is given by:$$v_d = \frac{I}{neA}$$where:* I is the current in amperes* n is the electron density in electrons/m^3* e is the electron charge in coulombs* A is the cross-sectional area in m^2Substituting the given values into the equation, we get:$$v_d = \frac{1.00 A}{(8.49 	imes 10^{28} electrons/m^3)(1.60 	imes 10^{-19} C)(4.00 	imes 10^{-4} m^2)}$$$$v_d = 1.84 	imes 10^{-6} m/s$$The direction of the drift velocity is opposite to the direction of the current density, so the correct answer is A.

The Electron Density in Copper Is 8