Question

why sensitive electric devices kept inside insulated metallic box.... please tell the answer of this question​

Answer 1

Sensitive electric devices kept inside insulated metallic box.

Answer:

This is because of the phenomenon called "Electrostatic shielding"

It's general that in all conductive materials, charges only reside on the surface of the conductor. Charges never reside at the center.

A Metallic box can be considered as a conductor. Even if we keep a sensitive electrical instrument inside it, the charges in the metallic box will be present only on the surface. As a result, electric field inside the metallic box is zero. Hence the electrical instrument kept inside it won't be affecred