Electrostatics Lab: Conservation of Charge (Electroscope)
Investigate the **Conservation of Electric Charge** by observing the charging of an electroscope. The total charge in an isolated system remains constant; charge is only transferred.
Key Equations & Concepts
â–¼Charge is conserved in an isolated system. Charge can only be transferred, not created or destroyed. $$ \Sigma Q_{\text{initial}} = \Sigma Q_{\text{final}} $$
When two identical conductors are brought into contact, the total charge ($Q_{total}$) is shared equally: $Q_1' = Q_2' = Q_{total}/2$.
Charge comes in discrete packets (quanta) and is always an integer multiple of the elementary charge ($e$): $$ Q = n \cdot e $$ where $e = 1.6 \times 10^{-19} \text{ C}$.
Experiment 1: Charging by Conduction Simulation
Bring a charged rod into contact with the electroscope to observe charge transfer and leaf deflection.
Scope is Neutral. Click 'Apply Rod' to charge by conduction.
Experiment 2: Charge Transfer Challenge (Quantization)
Calculate the final charge/potential or the number of electrons transferred during a sharing process.
The electroscope experiment confirms that when a charged object touches a neutral conductor, charge flows until both objects have the **same potential**. The total amount of positive and negative charge in the entire system never changes.
Electrostatic Potential and Capacitance (11th Std)
The **Electrostatic Potential** ($V$) of a charged sphere ($Q$) with radius ($r$) is: $$ V = \frac{1}{4\pi\epsilon_0} \frac{Q}{r} $$ Charge flows until the potentials ($V$) are equal.
The force ($F$) between the two leaves of the electroscope causing them to repel is governed by Coulomb's Law: $$ F \propto \frac{q_1 q_2}{r^2} $$
Electrostatic field lines originate from positive charges and terminate on negative charges. The leaves repel because the electric field pushes them apart.
