Understanding Electric Charge and Electroscopes

Charge

Property determining attraction or repulsion between objects.

Negative Charge

More electrons than protons in an object.

Positive Charge

More protons than electrons in an object.

Coulomb (C)

Unit of electric charge in the International System.

Electron Charge

Charge of an electron is 1.6×10⁻¹⁹ C.

Proton Charge

Charge of a proton is +1.6×10⁻¹⁹ C.

Gold Leaf Electroscope (GLE)

Device to detect and measure electric charge.

Electroscope Structure

Vertical metal rod with gold leaf inside glass.

Electroscope Function

Detects, distinguishes, and measures electric charge.

Charge Detection

Leaves move when a charged object approaches.

Charge Induction

Separation of charges without direct contact.

Earthing (Grounding)

Connecting a charged object to the ground.

Coulomb's Law

Force between charges is proportional to product of charges.

Electric Field

Region where electric forces can be experienced.

Electric Field Strength

Force per unit charge, measured in N C⁻¹.

Permittivity

Measure of how much a charge affects another charge.

Permittivity of Free Space

Value is 8.9×10⁻¹² F m⁻¹.

Electric Field Direction

Points away from positive charges, towards negative.

Electric Field Visualization

Semolina aligns in oil under electric field.

Force (F)

Proportional to product of charges and inversely to distance.

Distance (d)

Separation between two point charges in Coulomb's Law.

Known Charged Object

Used to determine unknown charge type in electroscope.

Metal Case Purpose

Shields electroscope from external electric fields.

Insulator Test

Contact with electroscope shows if object conducts.

Charge Magnitude Indication

Leaf separation indicates size of charge.