Stefan Boltzman Constant

Objective

To determine the Stefan Boltzman constant for radiation heat transfer.

apparatus

Diameter of test disc(d) = 20mm

Thickness of disc = 15mm

Mass of test disc(m) = 0.5g

Emissivity of Hemisphere = 0.072

Specific heat of copper = 380.3kJ/kgk

Emissivity of copper disc = 0.072

Inner Diameter of Hemisphere Surface = 200mm

Temp1(°C) 10
Temp2(°C) 10
Temp3(°C) 10
Temp4(°C) 10
T avg(°C) 10

Temperature Gradient

Move the cursor to the graph to see the points

Time Temperature
5 34.9
10 35.2
15 35.7
20 35.9
25 36
30 36.8
35 38.1
40 38.8
45 39.3
50 39.7
55 40.2

Please enter a value rounded upto two decimal points

Calculation
dT/dt= 0.11K/s
Q=m.Cp.(dT/dt)

Q =

W

Calculation
σ = m.Cp.(dT/dt)A(Tavg4- Td4)

σ =

x10-8W/m2k4