Assembling a Velocity Filter to Determine the Specific Electron Charge

The Assembling a Velocity Filter to Determine the Specific Electron Charge is designed to study the motion of electrons in crossed electric and magnetic fields. The apparatus demonstrates the principle of velocity selection by balancing the electric and magnetic forces acting on an electron beam. Under the correct operating conditions, only electrons with a specific velocity travel in a straight path, enabling a more accurate determination of the specific charge (e/m) of the electron. Manufactured by Atico Export India.

Principle

A Wien Filter uses mutually perpendicular electric and magnetic fields to separate charged particles according to their velocity. The electric field tends to deflect the electron beam in one direction, while the magnetic field produces an equal and opposite force. When these two forces are exactly balanced, the electron beam travels in a straight line without deflection. By measuring the applied electric and magnetic fields under this condition, the velocity and specific charge (e/m) of the electron can be determined with high accuracy.

Objectives

• Construct and study a Wien (velocity) filter.
• Investigate the motion of electrons in crossed electric and magnetic fields.
• Observe the condition for zero beam deflection.
• Determine the velocity of the electron beam.
• Calculate the specific charge (e/m) of the electron.
• Study the balance between electric and magnetic forces.

System Components

Electron Deflection Tube :

• Quantity: 1

Tube Stand :

• Quantity: 1

Pair of Helmholtz Coils :

• Quantity: 1

High Voltage Power Supply :

• Output: 10 kV
• Quantity: 2

DC Power Supply :

• Output: 0 to 16 V, 0 to 5 A
• Quantity: 1

Safety Connecting Lead :

• Length: 25 cm
• Color: Red
• Quantity: 2

Safety Connecting Lead :

• Length: 50 cm
• Color: Red
• Quantity: 1

Safety Connecting Lead :

• Length: 50 cm
• Color: Blue
• Quantity: 1

Safety Connecting Lead :

• Length: 100 cm
• Color: Red
• Quantity: 2

Safety Connecting Lead :

• Length: 100 cm
• Color: Blue
• Quantity: 4

Safety Connecting Lead :

• Length: 100 cm
• Color: Black
• Quantity: 2

Electron Deflection Tube :

• Provides clear visualization of the electron beam path.

Crossed Field Demonstration :

• Simultaneously applies electric and magnetic fields to the electron beam.

Velocity Selection :

• Allows only electrons with a specific velocity to travel without deflection.

Helmholtz Coil Assembly :

• Generates a uniform magnetic field for precise experimental measurements.

High Voltage Operation :

• Stable high-voltage supplies ensure reliable electron acceleration.

Educational Design :

• Ideal for studying charged particle motion, velocity selection, and electromagnetic principles.