1. Contact Charging (Conduction):
* Method: Bring a charged object (e.g., a charged rod) into direct contact with the electroscope's metal knob.
* How it works: Electrons are transferred from the charged object to the electroscope (if the object is negatively charged) or from the electroscope to the object (if the object is positively charged).
* Result: The electroscope acquires the same charge as the charged object.
2. Induction Charging:
* Method: Bring a charged object near the electroscope without making contact.
* How it works: The charged object repels or attracts electrons in the electroscope, causing a separation of charge. The leaves of the electroscope will diverge.
* Result: The electroscope becomes charged with an opposite polarity to the charging object. To permanently charge the electroscope, you need to ground the electroscope while the charged object is nearby. This allows excess charges of the opposite polarity to flow to ground, leaving the electroscope with the opposite charge.
3. Charging by Friction:
* Method: Rub a non-conducting material (like a plastic ruler) against a different material (like wool). This creates a static charge on the material. Then, touch the charged material to the electroscope.
* How it works: Friction causes the transfer of electrons between the two materials. The material that gains electrons becomes negatively charged, and the material that loses electrons becomes positively charged.
* Result: The electroscope acquires the charge from the rubbed material.
4. Charging by an Electric Field:
* Method: Place the electroscope in a strong electric field (e.g., near a Van de Graaff generator).
* How it works: The electric field forces the electrons in the electroscope to move, resulting in charge separation and divergence of the leaves.
* Result: The electroscope acquires a charge influenced by the direction and strength of the electric field.
Important Note:
* Positive Charge: An electroscope becomes positively charged if it loses electrons.
* Negative Charge: An electroscope becomes negatively charged if it gains electrons.
