P27_005

# P27_005 - − 19 C)(1 . × 10 5 m / s) = 6 . 4 A / m 2 ....

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5. (a) The magnitude of the current density is given by J = nqv d ,where n is the number of particles per unit volume, q is the charge on each particle, and v d is the drift speed of the particles. The particle concentration is n =2 . 0 × 10 8 / cm 3 =2 . 0 × 10 14 m 3 , the charge is q =2 e =2(1 . 60 × 10 19 C) = 3 . 20 × 10 19 C, and the drift speed is 1 . 0 × 10 5 m / s. Thus, J =(2 × 10 14 / m)(3 . 2 × 10
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Unformatted text preview: − 19 C)(1 . × 10 5 m / s) = 6 . 4 A / m 2 . Since the particles are positively charged the current density is in the same direction as their motion, to the north. (b) The current cannot be calculated unless the cross-sectional area of the beam is known. Then i = JA can be used....
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## This note was uploaded on 11/12/2011 for the course PHYS 2001 taught by Professor Sprunger during the Fall '08 term at LSU.

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