V-I curves of different light frequencies
(Click figure to enlarge)
Cutoff voltage vs light frequency
(Click figure to enlarge)
User interface panel of software
(Click photo to enlarge)
Features
Manual or auto measurement modes
Integrated structure and easy to operate
No crosstalk between spectral lines
Built-in data acquisition card with software for PC use via USB port
Introduction
This LEAI-52 experimental apparatus for determining Planck's constant is used to demonstrate the photoelectric effect, measure the characteristic curve of a photoelectric tube, verify the existence of "red limit" frequency, and calculate Planck’s constant according to the Einstein’s equation of photoelectric effect. By employing a precision photocell, Planck's constant can be determined with a high accuracy of 3%, either by processing data manually recorded from the apparatus; or by using a built-in data acquisition card to automatically acquire data to a PC via USB port and process the acquired data with software. It is an ideal teaching apparatus for physics laboratories at colleges and universities.
The instruction manual contains comprehensive materials including experimental configurations, principles and step-by-step instructions. Please click Experiment Theory and Contents to find more information about this apparatus.
Specifications
| Description | Specifications |
| Wavelength of filters | 365 nm, 405 nm, 436 nm, 546 nm, 577 nm |
| Size of apertures | 2 mm, 4 mm, 8 mm, 10 mm, 12 mm |
| Light source | 50 W Mercury lamp |
Photocell | Wavelength range: 340 ~ 700 nm |
| Cathode sensitivity: ≥1 µA (-2 V ≤ UKA ≤ 0 V) | |
| Anode dark current: ≤5×10-12 A (-2 V ≤ UKA ≤ 0 V) | |
| Current range | 10-7 ~ 10-13 A, 3-1/2 digit display |
| Voltage range | I: -2 ~ +2 V; II: -2 ~ +20 V, 3-1/2 digit display, stability ≤0.1 % |
| Zero drift | < ±0.2% of full scale (for scale 10-13 A) within 30 minutes after warm-up |
| Measurement method | Zero current method and compensation method |
| Measurement error | 3% |
Parts List
| Description | Qty |
| Main Unit | 1 |
| Electric Control Unit | 1 |
| Special BNC Cable | 2 |
| USB Cable | 1 |
| Software CD | 1 |
| Power Cord | 1 |
| Instructional Manual | 1 |
V-I curves of different light frequencies
(Click figure to enlarge)
Cutoff voltage vs light frequency
(Click figure to enlarge)
User interface panel of software
(Click photo to enlarge)
