Question

what is
an electroscobe?​

Answer 1

The electroscope is an early scientific instrument used to detect the presence of electric charge on a body. It detects charge by the movement of a test object due to the Coulomb electrostatic force on it. The amount of charge on an object is proportional to its voltage

Answer 2

OR

an instrument for detecting and measuring electricity, especially as an indication of the ionization of air by radioactivity.