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In a metal in the solid state, such as a...

In a metal in the solid state, such as a copper wire, the atoms are strongly bound to one another and occupý fixed positions. Some electrons (called the conductor electrons) are free to move in the body of the metal while the other are strongly bound to their atoms. In good conductors, the number of free electrons is very large of the order of `10^(28)` electrons per cubic metre in copper. The free electrons are in random motion and keep colliding with atoms. At room temperature, they move with velocities of the order of `10^5` m/s. These velocities are completely random and there is not net flow of charge in any directions. If a potential difference is maintained between the ends of the metal wire (by connecting it across a battery), an electric field is set up which accelerates the free electrons: These accelerated electrons frequently collide with the atoms of the conductor, as a result, they acquire a constant speed called the drift speed which is given by `V_e =` 1/enA where I = current in the conductor due to drifting electrons, e = charge of electron, n = number of free electrons per unit volume of the conductor and A = area of cross-section of the conductor.
If no potential difference is maintained between the ends of a conductor

A

the free electrons are at rest

B

the free electrons move randomly in all directions

C

the rate at which electrons pass through a certain cross-section from right to left is equal to the rate at which electrons pass through it from left to right

D

no current flows through the conductor.

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The correct Answer is:
B, C, D
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