Experiment 3

Definition: An electric field is a region around a charged particle where a force would be experienced by other charged particles.
Source of Electric Field: Always associated with charge.
Requires separation of positive and negative charges to create an electric field.

Description: Behaves like a battery; can select various voltages (e.g., 4V, 6V, 9V, 10V).
Specific Setting for Experiment: Used at 10 volts.
Features:
- Power switch (on/off).
- Two terminals (black and red), labeled plus (+) and minus (-).

Function: Measures voltage, current, and resistance.
For this experiment, it will be set to measure voltage.
Voltage Types:
- AC Voltage: Denoted with a wavy line (alternating current).
- DC Voltage: Constant voltage (direct current).
Multimeter Settings: Set to 20-volts max scale for measurement of the 10-volt power supply.

Multimeter has two leads (wires with metal tips): red (positive) and black (negative).
The measurement taken is the voltage difference between these two probes.
Voltage also referred to as electric potential.
Electric potential: Defined at a single point; voltage defined as the difference between two points in the electric field.

Materials Required: Tray with water (high resistance but slightly conductive), aluminum plates (acting as parallel plate capacitors), and alligator clips for connections.
Procedure:
- Connect power supply to the plates using alligator clips.
- Plates are spaced apart by a distance of 16 cm.
- Water acts as a medium to allow current flow for measurements.

Using the black probe connected to the ground (0 volts) as a reference:
- Measure voltage on the positively connected plate; expect readings of ~10 volts where the power supply is connected.
- Over various points between the plates, voltage increases linearly from 0 volts close to negative plate to 10 volts near the positive plate.
Measurement Steps:
- Move probe across different positions and record voltage (e.g., 1.8V, 2.8V, up to 10V).
- Potential measured indicates existence of electric field.

Electric field defined as change in voltage per unit distance:
$E = \frac{\Delta V}{\Delta x}$
Units: volts per centimeter (V/cm) or volts per meter (V/m); equivalent to newtons per coulomb (N/C).
Experimentation should include measuring at 8-10 points, noting position and voltage for graphing.

Investigate changing the separation between plates (e.g., reduce to 7-8 cm) and measure again to find differing slopes in the graph.
Theory: As plates are brought closer together, they will draw more charge from the power supply at constant voltage (10V).
Explanation: Closer proximity increases attraction between positive and negative charges, resulting in stronger electric field.
- Note that charge density might increase as plates get closer thereby affecting field strength.

An alternative electric field measurement technique involves shifting probes in water and calculating potential differences over known distances (e.g., 2 centimeters apart).
Calculate electric field as follows:
$E = \frac{\Delta V}{\Delta x}$
where (\Delta V) is the change in voltage measured and (\Delta x) is the distance between probes.

Conductors placed in electric fields polarize, causing charge separation without total loss of neutrality.
Termination of electric field lines perpendicularly to conductors, thus, no electric field inside conductors (Faraday Cage principle). Therefore,
- In the interior of a conductive ring, voltage remains constant, hence zero electric field exists due to no potential difference inside.

Polarization of a conductor (metal ring placed in an electric field):
- Negative charges accumulate on one side of the conductor, creating a net positive charge on the opposite side.
- Resulting electric field lines terminate perpendicular to the surface of the conductor,
- This behavior manifests in real-world shielding applications like the Faraday Cage, used for protection against electric fields.

Demonstrates creation of non-uniform electric fields using two electrodes generating an electric dipole.
Measure potential at various points in proximity to the dipole to illustrate varying electric field strengths, illustrating field curvature and intensity.
Verify electric field direction using multimeter readings that yield voltage relative results.

Summary of findings indicates that electric fields are dependent on charge distribution and proximity between charge sources.
Various experimental techniques reinforce understanding of electric field principles, allowing for quantitative measurements leading to visual confirmations via graphs of electric potential variation along defined paths.
Encourages further exploration of electric fields in different configurations to enhance understanding of underlying principles in electrostatics and practical applications.