Experiment Stephan-Boltzmann law

Subjects discussed :
- Black body radiation
- e.m.f. thermoelectric
- Dependence of resistance on T°

Principles and objectives:
According to the Stefan-Boltzmann law, the energy emitted by a black body per unit area and per unit time is proportional to the "fourth" power of the absolute temperature of the body. The Stefan-Boltzmann law is also valid for a so-called "gray" body whose surface has an absorption coefficient independent of wavelength less than one. In the experiment, the "gray" body is represented by the filament of an incandescent lamp whose energy emission is studied as a function of temperature.
The first experimental part consists of measuring the resistance of the filament of the incandescent lamp at room temperature and determining the resistance R0 of the filament. Secondly, the energy flow density of the lamp is measured at different heating voltages. The corresponding heating currents are recorded for each heating voltage and the corresponding filament resistance is calculated.

Composition :
- Optical bench l = 60 cm / Adjustable foot for optical bench
- Jumper for optical bench, h = 80 mm
- Universal measurement amplifier
- Thermopile according to Moll / Protection tube
- Variable transformer with rectifier DC: 12 V, 5 A / AC: 15 V, 5 A
- Socket, E14, on stem / Incandescent lamp 6V / 5A, E14
- Connection Box / Resistor 100 Ohm 2%, 1w, G1
- Digital multimeter with thermocouple
- Connection wires, 32 A, 500 mm