How can you tell whether an electric field is present?

Answer 1

Depends on the electrical field, but the most common way to tell is the metallic smell of ionized oxygen or ozone, a tingly feel on the skin, and hair standing on end. But that's only for strong electric fields. For weak electric fields the use of a some sort of meter is required.

Answer 2

You can use an electric field sensor or a charged object to detect the presence of an electric field. The sensor will measure the electric field strength, while the charged object may experience a force or movement when placed in an electric field. Additionally, observing the behavior of charged particles in the presence of the field can also indicate its presence.