Question

A sensitive magnetic instrument can be shielded very effectively from outside magnetic fields by placing it inside a box of:

• A. wood
• B. plastic
• C. metal of high conductivity
• D. soft iron of high permeability

Answer 1

Answer: (D)

The measurement of the sensitive magnetic instruments are influenced by the external magnetic field. So these instruments need to be shield from external magnetic field, This is done by placing a soft iron core of high permeability around it. The magnetic flux gets established inside the soft iron rather than the sensitive magnetic device and so the device is shielded.