A silver wire 2.6 mm in diameter transfers a charge of 420 C in 80 min. Silver contains 5.0 x 10^28 free electrons per cubic meter. (a) What is the current in the wire? (b) What is the magnitude of the drift velocity of the electrons in the wire?

a) 0.0875A

b) 2.06*10^-6m/s

Explanation:

given

Diameter, d = 2.6mm = 0.0026m

Charge, Q = 420C

Time, t = 80mins = 80*60s = 4800s

Concentration of electrons, n = 5*10^28

To find the current, recall that q = it

Therefore, i = Q/t

Current, i = 420/4800

i = 0.0875A

To get the drift velocity, recall that I = n*q*Vd*A

A = πd²/4

A = π*0.0026²/4

A = 5.3*10^-6m²

Then, Vd = I/nqA

Vd = 0.0875/(5*10^28 * 1.6*10^-19 * 5.3*10^-6)

Vd = 0.0875/42400

Vd = 2.06*10^-6m/s

Note, low Vd causes low current.

Therefore, the current is 0.0875A and the Vd is 2.06*10^-6m/s

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.