A copper wire has a circular cross section with a radius of 1.00 mm. (a) If the wire carries a current of 2.50 A, find the drift speed of the electrons in the wire. (Assume the density of charge carriers (electrons) in a copper wire is n

Complete question is;

A copper wire has a circular cross section with a radius of 1.00 mm.

(a) If the wire carries a current of 2.5 A, find the drift speed of the electrons in the wire. (Assume the density of charge carriers (electrons) in a copper wire is; n_e = 8.46 × 10^(28) electrons/m³)

V_d = 5.88 × 10^(-5) m/s

Explanation:

We are given;

Radius; r = 1 mm = 0.001 m

Current; I = 2.5 A

Number of electrons per m³; n_e = 8.46 × 10^(28) electrons/m³

Now, formula for drift velocity is;

V_d = I/(A × n_e × q)

Where;

I is current

A is Area = πr² = π × 0.001²

A = 0.001²π

q is electron charge = 1.6 × 10^(-19) C

Thus;

V_d = 2.5/(0.001²π × 8.46 × 10^(28) × 1.6 × 10^(-19))

V_d = 2.5/42524.59815899144

V_d = 5.88 × 10^(-5) m/s

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27