Question

If the magnetic field outside a copper box is suddenly changed, what happens to the magnetic field inside the box? Such low-resistivity metals are used to form enclosures which shield objects inside them against varying magnetic fields.

Answer 1

Answer:

low-resistivity metals are used to form enclosures which shield objects inside them against varying magnetic fields.

Answer 2

Explanation:

• The contrasting magnetic field generates eddy currents on the copper box walls. Because of the induced eddy currents there is a magnetic field, that is in the opposite direction.
• The magnetic field will therefore be effective due to the eddy currents, as copper has better conductivity. Because of the eddy currents the magnetic field generated in the copper walls cancels the initial magnetic area.
• Therefore, the magnetic area does’t reach the copper enclosure. The magnetic field stays zero inside the enclosure.
• That's how the copper panel inside the material protects against changing magnetic fields.