For protecting a sensitive equipment from the external magnetic field, it should be

For protecting a sensitive equipment form external magnetic field, it should be

Assertion: To protect any instrument from external magnetic field, it is put inside an iron body. Reason: Iron is a magnetic substance.

Assertion: To protect any instrument from external magnetic field, it is put inside an iron body. Reason: Iron is a magnetic substance.

in presence of external magnetic field, f subshell is

If you want to protect a very sensitive instrument from presence of any external electric field, you will