This document describes an experiment measuring the radiation intensity of black objects as a function of temperature based on the Stefan-Boltzmann law. The experiment uses an electric oven fitted with a black body accessory to heat objects to temperatures between 300-700°C. A thermopile and temperature sensor are used to measure radiation intensity and temperature respectively, with the data collected by a computer program. The results show that radiation intensity increases with the fourth power of temperature, in agreement with the Stefan-Boltzmann law. Analysis of temperature and cooling rate over time also match theoretical models. The experiment confirms theoretical understandings of black body radiation.

1. MEASURING RADIATION INTENSITY OF OBJECTS
BLACK AS A FUNCTION OF TEMPERATURE (STEFAN-BOLTZMANN LAW)
Dwi Maryanti Putri*, Meili Yanti, Nurul Muthmainnah Herman
Laboratorium Fisika Modern Jurusan Fisika FMIPA
Universitas Negeri Makassar
Abstract. Experiments Measuring Radiation Intensity as a Function of Temperature dark matter (Stefan-
Boltzmann Law) aims to measure the intensity of radiation (relative) of a black body at a temperature range of
3000 C - 7000 C with a Moll thermopile and determine the relationship between the intensity of the radiation to
absolute temperature (Law Stefan- Boltzmann. Ekesperimen using an electric oven is equipped with accessories
black body would serve as 'an ideal black body'. the temperature sensor using a NiCr-Ni thermocouple connected
to a data logger to the computer Cassy. thermal radiation was measured using a thermopile Moll connected to
Cassy V box. the experimental results showed that the rate of the fourth power of the black body temperature
obtained using the analysis graph between log V (volts) with log T (kelvin) is |4.08 ± 2.62|the value is the value
of the rank of the temperature with accuracy levels of 55 , 1% and the ratio of cooling Newton's law constants (K
values) in theory, namely | -0.00015 ± 0.00004 | and the graph is | -0.000089 ± 0.00008 | with a degree of confidence
that is 91.5%.
KEYWORDS: Radiation Black body , Temperature, Newton's Law of Cooling, Black Objects.
INTRODUCTION
Thermal (heat) from the sun to the earth
via electromagnetic waves. The move is called
radiation, which can take place in a vacuum.
Radiation emitted by an object as a result of
temperature is called heat radiation (thermal
radiation).
Each object continuously emit heat
radiation in the form of electromagnetic waves,
but generally things look to us because it
reflects the light that came to him, not because
he memacarkan heat radiation. New objects
appear as radiating heat if the temperature
exceeds 1000 K. Once the temperature of the
object to be improved, the relative intensity of
the spectrum of light it emits changes. This
causes a shift in the colors of the spectrum are
observed, which can be used to estimate the
temperature of an object.
Black body radiation is one of the great puzzle
of physics that triggered the revolution in
physics. This revolution gave birth to quantum
physics. Research on black body radiation
involves a lot of scientists.
There is no perfect black body. We can
only create objects that are closer to a black
body. although the surface of the box was
painted white Why is that? When radiation from
sunlight entering the pit box, the reflected
radiation repeatedly (several times) by the walls
of the box and after this reflection hamoir can
say no more radiation left over (all radiation has
been absorbed in the box) in other words, the
hole has been functioning absorbs all radiation
that came to him as a result of objects appear
black.
In the experiment "Intensity radisasi
determine the black body as a function of
temperature" aims to prove the experiments
conducted by the Max Planck Institute, which
filed hipotesisyang Planck contrary to the
classical theory of electromagnetic waves
which is the beginning of the birth of quantum
theory.
Quantum theory is very important in science
because, in principle, in theory could be used to
predict chemical properties and physics of a
substance [2]
In addition to determining the radiation
intensity, this lab also aims to teach the
scientific practitioner attitudes shown by
scientists conducting experiments in the past, so
that it can serve as an example and can be
applied in the process of this investigation.
The method used to determine the black body
radiation is by comparing the increase in
temperature of an object and its surface
properties, in which a black object absorbs heat
radiation at all wavelengths.
THEORI
Black body radiation is one of the great
puzzle of physics that triggered the revolution
in physics. This revolution gave birth to
quantum physics. Research on black body
radiation involves a lot of scientists. One of

2. them is Kirchhoff, a professor of physics at the
meeting Heidelberg.Kirchhoff found that the
spectral intensity, ie the intensity per unit
wavelength and per unit solid angle, from a
black body is a function of wavelength and
temperature but does not depend on the
dimensions of a black body the. In his writings,
Kirchhoff stresses the importance of finding the
form of the function.
The density of black body radiation
spectral intensity has a simple relation with the
spectral power density (energy per unit
wavelength per unit volume) of black body
radiation in the cavity. However, to prove it is
necessary to measure the intensity of the
spectral density, which unfortunately, at the
moment it can not be done. This measurement
can only be done 20 years kemudian.Waktu that
physicists can measure the intensity of the
whole spectrum without knowing that the
intensity of this spectrum depends on the
wavelength.
Josef Stefan (1835-1893) in Vienna in
1879 who first discovered that the meeting of
the entire spectrum of energy is proportional to
the fourth power of the temperature of a black
body.
Five years later, LudwigBoltzmann
(1844-1906) one of the leading pioneers of
statistical mechanics to introduce the concept of
radiation pressure, indicating that Stefan
empirical equation can be obtained theoretically
from the second law of thermodynamics.
Collaborative these two figures, Stefan and
Boltzmann, who started the first step in an effort
to discover the function of Kirchhoff. [4]
Kirchhoff (1859) shows the second law
of thermodynamics from that radias in bersifar
isotropic black body cavity, the radiation flux is
free from direction / orientation, then also are
homogeneous is equal to the radiation flux at
each point, and is the same in all the cavities at
a temperature the same for each wavelength.
Objects that absorb heat radiation at
wavelengths throughout the so-called black
body. Small hole in a hollow object behaves as
a perfect black body (this idea was first
proposed by Kirchhoff) [2]
Quantum theory began with the
phenomenon of black body radiation. When an
object is heated it will look emit radiation (eg
characterized by the emission of light colored).
Speaking of black body radiation means we talk
about objects that have the characteristics of a
perfect absorber of radiation that is about it. [3]
Principles Stefan-Boltzmann law states
that the total radiation emitted by an object is
proportional to the absolute temperature
increases the rank 4. Let the radiation emitted
from a surface is M (M = total radiated power),
then the amount of radiation emitted is defined
as,
4
M T (1)
with σ = 5,67 ⋅10-8 W/m2K4 (Stefan-
Boltzmann constant).
At the same time a black body absorbs
radiation from the environment. So measuring
the M but M 'which radiation is absorbed from
the environment. Radiation emitted by the
environment as it is written,
4
o oM T (2)
Thus obtained,
 4 4
' oM T T  (3)
An object that is not an ideal radiator also
satisfy the equation 3 her bag but has a
coefficient of absorption "e" whose value is less
than 1, so it is written:
4
TeE  (4)
Where, e = emissivity (0 ≤ e ≤ 1).
Radiation or light emission in solids show a
continuous spectrum as the heated gas. [2]
In 1894, Vienna with the idea that they
also generally show that the energy must be in
mathematical form as follows.







T
f
gfTfu 3
),( (5)
The above equation is the law of Wien. The
implications of this law are:
1. The distribution of black body radiation
spectrum for sembrang temperature can be
searched by the above formula.
2. When the function g(x) has a maximum
value for x> 0 then in force
T
b
maks  (6)

3. Planck proposed that a vibrating athom and
memncarkan can only absorb energy again in
the form of bundles of energy called quanta. If
the energy quanta is proportional to the
frequency of the radiation, the energy will also
be great anyway, but because none of waves
that can have energy exceeds kT, then tidaka da
standing wave that quantum energy greater than
kT. This effectively limits the intensity of the
radiation. Planck formulation of the intensity of
radiation can be used to derive the law of Stefan
and Wien shift law, and in fact decrease Stefan
law of Planck's formula gives the Stefan-
Boltzmann constant relationship and tetpan
Planck [1]
EXPERIMENTAL METODHOLOGY
Every object radiates heat. The
intensity of heat radiation (electromagnetic
nature) increases with increasing temperature of
objects, as well as dependent on the nature of
the surface. At a particular wavelength, the
greater the heat radiation emitted, the greater the
heat radiation is absorbed by the object.
Objects that absorb heat radiation at
wavelengths throughout the so-called black
body. Small hole in a hollow object behaves as
a perfect black body (this idea was first
proposed by Kirchhoff). The tools and materials
in this experiment are:
1. A set of tools GmBH Leybold production
experiment, which consists of an electric
oven to 230 V voltage, Accessories black
object, Safety box with a ground connection,
Sensor Cassy, Cassy Lab, adapter NiCr-Ni,
NiCr-Ni temperature sensor 1.5 mm, box
μV, termofile Moll, a small optical bench,
shortrod, Buffer V-shaped, 28 cm,
Multiclamp Leybold, universal Clamp, and a
pair of 100 cm cable, red / blue.
2. Supplement: 1 PC with Windows 98
operating system or higher
3. Other equipment is recommended that
Satuimmersion pump 12 V, Satulow-voltage
power supply, One silicone tubing, 7 mm Ø,
and One laboratory bucket, 10 l.
Before observing the intensity of black
body radiation, we first learn all the components
that have been installed correctly so it does not
need to be setup again. After that we connect all
of the tools to a voltage source including a
computer that will be used in the data collection.
In this experiment, before turning on an
electric oven that has been fitted by a black
body accessory to first run the water pump for
approximately 2 minutes. After 2 minutes the
oven is turned on and wait until the temperature
rises 5000C oven, where the temperature
change is observed on the screen of computer
software that has been equipped with Cassy
Lab.
FIHURE 1. The series of experimental tools
Radiation Black Objects
In order Cassy enabled NiCr-Ni
temperature sensors and μV box and set the
temperature measurement range from 00C-
12000C and voltage of -3 mV - 3 mV.
Furthermore, observed changes in the intensity
of the radiation as a function of the temperature
at which we are going to wait for 1 hour or more
until the temperature reaches above 4000C.
when the temperature reaches 4000C started
recording measurement data by pressing the
symbol on the menu Cassy and stop recording
when you are at a temperature of 500C. it stores
data after the recording by clicking on the save
symbol on the menu Cassy.
FIGURE 2. Display Settings menu Cassy and
temperature sensors and voltage

4. EXPERIMENT RESULT AND DATA
ANALYSIS
After the observation of the values
obtained 400oC temperature produces a voltage
of 24.2 x 10-4
volts and when it is at a
temperature of 50 ° C produces a voltage of 2 x
10-6
volts, so from the above data shows that the
temperature of an object is directly proportional
to the voltage generated. The time required from
400o
C to 50o
C temperature is 7532 seconds.
The graph plots the results of the
relationship between voltage (log V) with
temperature (log T) to determine the value of
the fourth power of the temperature of the black
body is shown as a graph as follows.
FIGURE 3. Relationship between log V graph
and log T
Equation is linear in the graph log (T)
and log (V) is used for the radiation intensity
menganilisis relationship with the fourth power
of the temperature.
The analysis of the data:
I= 𝑒𝜎𝑇4
Note:
Eσ is a constant value, since the experiment
used is V, then::
V=T4
Log V= log T4
Log V= 4 log T
4=
log 𝑉
log 𝑇
DK= R2
x 100%
KR= 100%-DK
∆p=R2
m
PF= |𝑝 ± ∆𝑝|
Thus, the analysis of the graph
y = 4,7501x - 17,205 dan R² = 0,551
m= 4,7501
Note: the value of m = p, so:
The p-value = 4.7501 is the value that indicates
the rank of the absolute temperature as
equation shown in the intensity of black body
radiation Stefan-Boltzmann law.
The degree of confidence (DK) = R2
x 100%
= 55,1%
The relative error (KR) = 100% - DK = 44,9 %
Value Δp = R2
x p = 0.551 x 4.07501 = 2,62
Scientifically graph analysis results are reported
in two significant figures
𝑝 = |4.08 ± 2.62|
Figure 4. Graph of time relationship (s) on the
temperature (K)
The analysis of the data:
r=𝑟𝑜 𝑒−𝑘𝑡
.
𝑟
𝑟𝑜
= 𝑒−𝑘𝑡
.ln
𝑟
𝑟𝑜
= −𝑘𝑡
y = 4,7501x - 17,205
R² = 0,551
-6
-5
-4
-3
-2
-1
0
2,4 2,5 2,6 2,7 2,8 2,9
LOGV(v)
LOG T(O K)
y = 575,75200506e-0,00008996x
R² = 0,91499935
0
100
200
300
400
500
600
700
800
0 2000 4000 6000 8000
(SUHU(OK)
WAKTU (S)

5. -k=
𝑙𝑛
𝑟
𝑟 𝑜
𝑡
k=−𝑙𝑛
𝑟
𝑟𝑜
∆k=R2
k
PF= |𝑘 ± ∆𝑘|
To analyze the cooling constants used Newton
equation of a line generated by a graph of time
and temperature. The equation of the line:
y = 575,75200506e-0,00008996x
and R² =
0,91499935
then,
T = 575,75200506e-0,00008996x
and R² =
0,91499935
Value of k = -0.00008996 s-1
is a constant
value that indicates cooling Newton.
The degree of confidence (DK) = R2
x 100%
= 91.5%
The relative error (KR) = 100% - DK
= 8.5%
Value Δk = R2
x k
= 0,91499935 x (-0,00008996)
= - 0.0000823 s-1
Scientifically graph analysis results are reported
in two significant figures
𝑘 = |−0.000089 ± 0,000082| s-1
The average value of Newton's constant
cooling obtained by using the equation
t
r
r
k
)ln(
0
 is equal to 0.00019.
Based on the above analysis can be
more pronounced if the temperature rank (p)
and the value of Newton's constant cooling of
the analysis presented in the following table.
Table 1. Comparison of Rank Value T In
Experiments With Reference Value
rank T
Reference 4
Experiment/plot
graph
𝑝 = |4.08 ± 2.62|
Table 2. Comparison of Cooling Newton's
Constant Value In Calculations With Garik Plot
Constant k (s-1
)
Experiment/
plot graph
𝑘 = |−0.000089 ± 0,00008| s-1
Counting 0.00019 s-1
Based on the above analysis of the data
obtained by a graph of temperature to voltage,
overall it appears that the temperature is
proportional to the voltage. However, based on
the equation of the line formed by the graph of
the results obtained the rank of black body
temperature is |4.08 ± 2.62|. Value obtained
exceeds the value of the theory is 4. With a
55.1% degree of accuracy. The results differ
from theory due to the maximum temperature
used is not reached 5000
C and the level of
sensitivity of NiCr-Ni temperature sensor. So
from the experimental results is said that the
temperature of the rank of four (T4
) is directly
proportional to the voltage bersesuain the
Stefan-Boltzmann law.
Of the value equation of the line that is
contained in the graph, we can determine the
value of K to see that there is an exponential
equation of the line on the graph. Exponential
rank value on the graph is a plot of the value of
k is |−0.000089 ± 0,00008|𝑠−1
with a degree
of confidence that is 91.5%. When compared
with the value obtained by the calculation of the
value of k is |−0,00015 ± 0,00004|
CONCLUSION
The intensity of black body radiation
(represented by voltage) is proportional to the
temperature rise in rank 4 and those obtained
from experiments that |4.08 ± 2.62|. K values
obtained in theory or calculation |−0,00015 ±
0,00004| and from the equation K values
obtained by |−0.000089 ± 0,00008|𝑠−1
.

6. REFERENCE
[1].Kenneth Krane. 1992. Fisika Modern.
Terjemahan H. J. Wospakrik. Jakarta, Penerbit
Universitas Indonesia (UI-Press).
[2]. Malago, Jasruddin Daud. 2005. Pengantar
Fisika Modern. Badan Penerbit UNM.
Makassar.
[3]Serway, Raymond. J . 2010. Fisika untuk
Teknik dan Sains Edisi Keenam Buku Tiga.
Jakarta : Erlangga
[4].Subaer, dkk. 2014. Penuntun Praktikum
Eksperimen Fisika I Unit Laboratorium Fisika
Modern Jurusan Fisika FMIPA UNM.