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

The correct option is D soft iron of high permeability

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.