When the leaves of an electroscope are spread apart: a. A negatively charged object must be touching the knob of the electroscope. b. The leaves have the same charge. c. A positively charged object must be touching the knob of the electroscope. d. The leaves are neutral.

B. The leaves have the same charge.

Explanation:

An electroscope is a device used to detect the presence of electric charges. However, to detect charge in an object, it requires hundreds of volts, that's why is only used with high voltage sources.

An important matter is that an electroscope follows the Coulomb electrostatic force, which is a law of physics that quantifies the amount of force between two charged particles, which are stationary.

Having said that, when two charged particles have the same nature, then they will spread apart. Same nature means both negative or both positive.

Therefore, the right answer is B.

B

Explanation:

The electroscope device is used to detect the presence of charge and it's relative amount. If a charged object is brought near the top of the electroscope (for a example positive charge) the leaves at the bottom spread apart. The leaves diverge further: The positive charge on the leaves has increased further. This happens when positive charge is produced on the leaves by the charged object. This is possible when the object is positively charged. The greater the charge, the farther apart they move.