Coulomb's Law Apparatus

The Coulomb's Law Apparatus is designed to demonstrate and verify Coulomb's Law, which states that the electrostatic force between two electrical charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. The apparatus enables students to accurately measure charge, force, and distance between two conductive spheres. One sphere is mounted on an insulating, counterbalanced rod suspended by a torsion wire, while the other sphere can be positioned at different distances. The symmetrical construction minimizes measurement errors, and the built-in magnetic damping ensures fast and accurate observations. Manufactured by Atico Export India.

Principle

Coulomb's Law states that the force between two electrical charges is proportional to the product of the charges and inversely proportional to the square of the distance between them. When the conductive spheres are charged, the electrostatic force between them twists the torsion wire. The amount of twist required to restore equilibrium is proportional to the electrostatic force acting between the spheres.

Objectives

• Verify Coulomb's Law experimentally.
• Determine the inverse square relationship between electrostatic force and distance.
• Measure charge, force, and distance between two conductive spheres.
• Study the relationship between electrostatic force and separation distance.
• Investigate variables affecting electrostatic repulsion.

Torsion Balance Assembly :

• 38 mm diameter conductive sphere mounted on a 12 cm rod with counterbalance vane.

Torsion Balance Degree Plate :

• 1° increments.

Magnetic Damping :

• Damps oscillations for rapid measurements.

Linear Track Sphere :

• 38 mm diameter conductive sphere.

Calibration Masses :

• 50 mg (1)
• 20 mg (2)

Conductive Sphere on Insulating Thread :

• Used for reducing charge by fixed ratios.

Spare Torsion Wire :

• 1 m

EHT Power Supply :

• 6 kV (Not Included)

Charging Probe :

• 17 cm long with 1.5 m cable and banana plug connector.

What's Included

• 1 × Coulomb's Law Apparatus
• 1 × Charging Probe
• 1 × Calibration Masses
• 1 × Calibration Post
• 1 × User Manual

Required Accessories

EHT Power Supply :

• 6 kV power supply (Not Included)

Built-in Balance Scale :

• Degree scale on the torsion balance provides accurate measurements of the torsion wire's twist angle.

Magnetic Damping :

• Reduces oscillations for quick and accurate measurements.

Calibration Masses :

• Enables determination of the torsion constant and verification of its linearity.

Built-in Track Scale :

• Millimeter scale on the linear track provides accurate distance measurements between the conductive spheres.

Symmetrical Construction :

• Minimizes errors caused by stray and mirror charges for improved measurement accuracy.