Which of these metals provide magnetic shielding?

[lioric]

Homework Statement

This a question from an olevel paper and the marking scheme says B
I don't understand why

Homework Equations

None a theory question

The Attempt at a Solution

Aluminum and copper has less magnetic property while iron is good magnetic material. I cannot understand why the paper clips should fall when iron is inserted and not fall when copper is inserted.

 

[scottdave]

The magnetic lines of force pass through non magnetic materials like the cardboard and non-ferrous metals. They interact with magnetic metals like the iron in the paperclips. But a sheet of magnetic metal will cause the lines of force to redirect, and they are no longer passing through the paperclips.

 

[lioric]

The magnetic lines of force pass through non magnetic materials like the cardboard and non-ferrous metals. They interact with magnetic metals like the iron in the paperclips. But a sheet of magnetic metal will cause the lines of force to redirect, and they are no longer passing through the paperclips.

Thank you very much