Stefan Boltzmans Apparatus
Product Code : EL-HTL-11089
Quick answer: The Stefan-Boltzmann apparatus is used to find the Stefan-Boltzmann constant by experiment. A 200 mm copper hemisphere in a hot water jacket radiates onto a blackened 20 mm copper disc at its centre, and a 0.1 °C digital indicator with a 5 second buzzer tracks how fast the disc warms. Lab Exports manufactures it in Delhi for engineering colleges, polytechnics and TVET institutes.
Specifications
| Component | Specification |
|---|---|
| Water heating tank | With electric immersion heater |
| Hemisphere | Copper sheet, 200 mm dia., in a 250 mm dia. water jacket |
| Test disc | Copper, 20 mm dia., blackened, thermocouple at centre |
| Temperature indicator | Multichannel digital, 0 to 200 °C, 0.1 °C least count |
| Timer | Audible buzzer every 5 seconds |
| Services | 230 V, 15 A AC supply with earthing; bench area 1 x 0.5 m |
How the Stefan-Boltzmann experiment is done
The Stefan-Boltzmann law states that a black body radiates energy at a rate proportional to the fourth power of its absolute temperature, E = sigma T^4. In the apparatus the hemisphere, held at a steady high temperature Th by the hot water jacket, radiates to the cooler disc at Td. The disc gains heat at m c dT/dt = sigma A (Th^4 - Td^4), where m, c and A are the mass, specific heat and exposed area of the disc.
Measuring the initial rate of temperature rise, dT/dt, from readings taken at each 5 second buzz, gives sigma = m c (dT/dt) / (A (Th^4 - Td^4)). Students compare their value with the accepted 5.67 x 10^-8 W/m^2 K^4.
- Heat the water in the tank with the immersion heater and fill the jacket around the hemisphere.
- Let the hemisphere reach a steady temperature and record it.
- Insert the blackened disc at the centre of the hemisphere.
- Record the disc temperature at every 5 second buzz.
- Plot disc temperature against time, find the initial slope and calculate sigma.
Key features
- Copper hemisphere, 200 mm dia., in a 250 mm water jacket as a steady radiant source
- Blackened 20 mm copper test disc with a thermocouple at its centre
- Digital temperature indicator, 0 to 200 °C with 0.1 °C least count
- Audible buzzer every 5 seconds for evenly spaced readings
- Water heating tank with electric immersion heater
Documentation and supply
Installation instructions and a manual are supplied with the apparatus. Most Lab Exports products carry a one-year manufacturer warranty.
Lab Exports manufactures the Stefan-Boltzmann apparatus at its works in Laxmi Nagar, Delhi, and supplies it to engineering colleges, polytechnics and TVET institutes in India and 60+ countries, handling the export documents for each shipment. More about the company is on the About Lab Exports page.
Related Heat Transfer Lab products
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- Critical Heat Flux Apparatus (EL-HTL-11090)
- Heat Transfer in Agitated Vessel (EL-HTL-11087)
- Concentric Tube Heat Exchanger (EL-HTL-11091)
- Shell Tube Heat Exchanger Water to Water (EL-HTL-11092)
- Specific Heat of Air Apparatus (EL-HTL-11085)
The full range is in the Heat Transfer Lab section of the Engineering Lab range.
Frequently asked questions
What does the Stefan-Boltzmann apparatus determine?
It determines the Stefan-Boltzmann constant from the rate at which a blackened disc warms when it receives radiation from a hot hemisphere.
Why is there a buzzer timer?
The buzzer sounds every 5 seconds so disc temperatures are read at equal intervals for the temperature-time plot.
What is the price of the Stefan-Boltzmann apparatus?
Prices are not published on the website. Add the Stefan-Boltzmann apparatus to the Enquiry Cart with the Add To Cart button on this page, or email [email protected] with the house code EL-HTL-11089 and the quantity, to receive a quotation.
Does Lab Exports manufacture the Stefan-Boltzmann apparatus?
Yes. Lab Exports manufactures the Stefan-Boltzmann apparatus at its works at 11/315, Lalita Park, Laxmi Nagar, Delhi 110092, under house code EL-HTL-11089.
Request a quote
Email [email protected] with the house code EL-HTL-11089 and the quantity, or add the Stefan-Boltzmann apparatus to the Enquiry Cart with the Add To Cart button on this page. Tender buyers can also see the Tenders and OEM page.