Question

When electric current is flowing in a metal, the electrons are moving.A. at nearly the speed of lightB. at the speed of lightC. at the speed of sound in the metalD. at the speed of sound in airE. at none of the above speeds

Answer 1

I believe its E.

Traveling through metal, electrons can not go the speed of light

Answer 2

E. at none of the above speeds

Step-by-step explanation:

When current flowing through the metal then the speed of electrons in metal is not very high.

This speed of all electrons inside metal is opposite the the electric field which is due to the applied potential difference on the metal by external battery.

As we know that

`\Delta V = i R`

here for the current flowing in the metal the all the free electrons will move at drift speed which is given as

`i = neAv_d`

here speed of electrons will be

`v_d` = drift speed

n = number density of electrons

A = crossectional area

e = charge of an electron

in general this speed is very small and approximately of order cm/s