Question

Conduction electrons are almost uniformly distributed within a conducting plate. When placed in an electrostatic field $\overrightarrow{E}$ the electric field within the plate

• A. depends upon E
• B. is zero
• C. depends upon the atomic number of the conducting element
• D. depends upon $\overrightarrow{E}$

Answer 1

The correct option is B is zero

Redistribution of charges and Electric field inside the conductor:

When external electric field $\overrightarrow{E}$ is applied, then the free electrons of the conductor are redistributed, they are attracted by the applied electric field and hence negative and positive charges appear on the surface of the conductor as shown in the figure.

Due to the charges appearing on the surface (also called induced charges), an electric field is generated which is opposite in direction to the applied electric field. Thus, the net electric field will be the superposition of the external electric field and Electric field due to induced charge.
$E_{net}=E_{ext}-E_{induced}$
Since the conductor has enough free electrons, so if $E_{net}$ is not zero, then it will exert force on the free electrons inside the conductor. And, redistribution of charges take place further, and more charges will accumulate on the surface and $E_{induced}$ will keep on increasing. This process will continue till the time $E_{net}$ becomes zero i.e.
$\Rightarrow {\overrightarrow{E}}_{ext}={\overrightarrow{E}}_{induced}$

So, in static situation, inside electric field will be zero always, does not depends upon external electric field, as induced charge will be in such a way so that net electric field could be zero inside the conductor.
Hence, option (a) is correct.