Chapter 21, Problem 72A

To determine

To Explain:The delicate parts of electric equipment contained within metal box.

Explanation of Solution

Introduction:

The delicate parts of electric equipment are kept within a metal box to protect it from external electric fields which might harm the parts. Electric fields induce current in electronic devices which cause damage.

To protect the delicate electronic parts from external magnetic field, they are kept inside metal boxes as the electric field inside a conducting metal box is zero. This is because an external electric field induces a positive charge on the outer surface and the other side becomes negatively charged. This forms an internal electric field which cancels out the external field.

Conclusion:

The delicate parts of electric equipment are kept within a metal box to protect it from external electric fields.