Question

Two identical conductors of copper and aluminium are placed in an identical electric field. The magnitude of induced charge in the aluminium will be:
(A) Zero
(B) Greater than in copper
(C) Lesser than in copper
(D) Equal to that of copper

Answer 1

We are asked about the magnitude of induced charge in the given aluminum sample. We can start by stating what materials the given samples are. Then we can move onto the working of electrons on the surface of each of the metals and thus giving us an idea about the induced charge in aluminum and its relation to that of copper.

Complete answer:
Let us start to attempt this question by stating the type of materials given. Copper and aluminum are metals. Metals have the capability to conduct electricity, that is, they are conductors. When these materials are subjected to an electric field, the mobile electrons that are responsible for the conduction property get aligned to the surface of the metal. This eternal electric field causes the induction of surface charges that causes the cancelation of the electric field within the metal. Since the magnitude of the external electric field is the same, the induced charge will be the same in both copper and aluminum.
In conclusion, the right answer is option (D) Equal to that of copper.

Note:
In a metal, there are mobile electrons present that help in the process of conduction of electricity. Electrons are negatively charged particles and hence they repel one another. In order to reduce this repulsion, they get aligned on the surface of the metal or a conductor and the net charge inside a conductor becomes zero. When there are no charges present inside a conductor, then there is no electric field as well.