Determining Planck’s Constant Selection of Wavelengths Using Interference Filters on the Optical Bench

The Determining Planck’s Constant Selection of Wavelengths Using Interference Filters on the Optical Bench is designed to determine Planck's constant by studying the photoelectric effect. The apparatus uses a photocell illuminated with monochromatic light of different wavelengths obtained through interference filters. The stopping potential is measured using a capacitor method and an electrometer amplifier, enabling accurate verification of the relationship between photon energy and stopping voltage. The experiment provides a practical demonstration of quantum theory and the photoelectric effect. Manufactured by Atico Export India.

Principle

The experiment is based on the photoelectric effect, where electrons are emitted from a photosensitive surface when illuminated by light of sufficient frequency. The emitted electrons are opposed by a stopping potential generated across a capacitor. The stopping voltage is measured without current using an electrometer amplifier. By repeating the measurements with different wavelengths of monochromatic light, the relationship between photon energy and stopping potential is established, allowing the determination of Planck's constant.

Objectives

• Determine Planck's constant using the photoelectric effect.
• Study the relationship between photon energy and stopping potential.
• Investigate the effect of light wavelength on photoelectron emission.
• Verify the principles of quantum theory.
• Understand the operation of a photocell and the photoelectric effect.

System Components

Photocell for Planck's Constant Experiment :

• Quantity: 1

Photocell Holder :

• Quantity: 1

Optical Bench :

• Profile: S1
• Length: 0.5 m
• Quantity: 1

Clamp Rider with Clamp :

• Size: 75 × 65 mm
• Quantity: 2

Clamp Rider with Clamp :

• Size: 105 × 65 mm
• Quantity: 3

Interference Filter Holder :

• Quantity: 1

Interference Filter :

• Wavelength: 578 nm
• Quantity: 1

Interference Filter :

• Wavelength: 546 nm
• Quantity: 1

Interference Filter :

• Wavelength: 436 nm
• Quantity: 1

Interference Filter :

• Wavelength: 365 nm
• Quantity: 1

Lens in Frame :

• Focal Length: 100 mm
• Quantity: 1

Iris Diaphragm :

• Quantity: 1

High Pressure Mercury Lamp :

• Quantity: 1

Power Supply for Mercury Lamp :

• Quantity: 1

Electrometer Amplifier :

• Quantity: 1

Plug-In Power Supply :

• Output: 12 V AC
• Quantity: 1

Capacitor :

• Capacitance: 100 pF
• Quantity: 1

Push Button (Normally Open) :

• Quantity: 1

Clamping Plug :

• Quantity: 2

Analog Multimeter :

• Quantity: 1

Straight BNC Adapter :

• Quantity: 1

BNC to 4 mm Plug Adapter :

• Single Pole
• Quantity: 1

4 mm Coupling Plug :

• Quantity: 1

Distribution Box with Earthing Socket :

• Quantity: 1

Connecting Leads :

• Current Rating: 19 A
• Length: 50 cm
• Red/Blue Pair
• Quantity: 1

Connecting Leads :

• Current Rating: 19 A
• Length: 100 cm
• Yellow/Green
• Quantity: 2

Optional Component

Interference Filter :

• Wavelength: 405 nm
• Quantity: 1

Photoelectric Effect Demonstration :

• Provides accurate verification of Planck's constant.

Capacitor Method :

• Measures stopping potential without current flow for improved accuracy.

Electrometer Measurement :

• High-sensitivity electrometer amplifier enables precise voltage measurements.

Multiple Wavelength Selection :

• Interference filters provide monochromatic light at different wavelengths.

Precision Optical Alignment :

• Optical bench ensures accurate positioning of all optical components.

Educational Design :

• Ideal for studying quantum physics, photoelectric emission, and modern optics.