Robert Cinca - Physics
Part 3.2: My Excel Model
Part
Part 3.2:
3.2: My
My Excel
Excel Model
Model
I used an excel spread sheet iteratively to see if a small filament lamp could be
I I used
spread
iteratively
to
effectively
modeled
as a sheet
hot body
radiator.
used an
an excel
excel
spread
sheet
iteratively
to see
see if if a
a small
small filament
filament lamp
lamp could
could be
be
effectively
modeled
as
a
hot
body
radiator.
effectively modeled as a hot body radiator.
How the model works
How
the model
works
How
works
I used the
the model
data for
the 6.5V 0.30A Filament Bulb as the inputs for my excel model.
I I used
used the
the data
data for
for the
the 6.5V
6.5V 0.30A
0.30A Filament
Filament Bulb
Bulb as
as the
the inputs
inputs for
for my
my excel
excel model.
model.
These were:
These
These were:
were:
the wire diameter.
the
diameter.
the wire
length
of the wire, , and the cross-sectional area, , which was used to
the
wire
diameter.
the
length
of
wire,
, , and
calculate
wire’s
volume,
. cross-sectional
the
length the
of the
the
wire,
and the
the
cross-sectional area,
area, , , which
which was
was used
used to
to
7
-3
the
wire’s
volume,
.
,
is
19250kgm
.
calculate
the
density
of
Tungsten,
as
researched
on
the
internet
calculate the wire’s volume, .
7
-3
, , is
the
density
Tungsten,
researched
on
internet
-3 .
the
of of
Tungsten as
calculated
the 7 volume
and density.
is 19250kgm
19250kgm
.
the mass
density
of the
Tungsten,
as filament
researched
on the
the from
internet
the
mass
of
the
Tungsten
filament
calculated
from
the
volume
and
density.
the mass of the Tungsten filament calculated from the volume and density.
The model starts at room temperature (295K) and is iterated every 0.1ms.
The
The model
model starts
starts at
at room
room temperature
temperature (295K)
(295K) and
and is
is iterated
iterated every
every 0.1ms.
0.1ms.
(as defined in Part 3.1), I was able to work out
Using resistivity to equal
Using
resistivity
to
(as
I I was
work
the
Resistance
the following equation:
(where
is a to
constant
(as defined
defined in
in Part
Part 3.1),
3.1),
was able
able
to
work out
out
Using
resistivity using
to equal
equal
the
the
(where
is
from Resistance
the length using
and cross-sectional
area of the wire (as shown
in Part 3.1).
the
Resistance
using
the following
following equation:
equation:
(where
is a
a constant
constant
from
the
length
and
cross-sectional
area
of
the
wire
(as
shown
in
Part
3.1).
from the length and cross-sectional area of the wire (as shown in Part 3.1).
, is:
The total energy into the filament,
, , is:
The
is:
The total
total energy
energy into
into the
the filament,
filament,
where
is the power into the wire,
is the time
where
is
power
into
is
interval, is the potential difference
the resistance.
where and
is the
the is
power
into the
the wire,
wire,
is the
the time
time
interval,
interval, is
is the
the potential
potential difference
difference and
and is
is the
the resistance.
resistance.
To work out the changing potential difference, I used:
To
To work
work out
out the
the changing
changing potential
potential difference,
difference, I I used:
used:
The effective resistance is calculated to be:
The
The effective
effective resistance
resistance is
is calculated
calculated to
to be:
be:
The total energy out of the filament is defined treating it as a hot body radiator:
8 body radiator:
The
filament
defined
treating
it it as
, where
emissivity
of tungsten
of
0.35,
is Stefan-
The total
total energy
energy out
out of
of the
the
filament is is
is the
defined
treating
as a
a hot
hot
body
radiator:
8
9
, , where
the
of
0.35,
Boltzmann’s constant , and
is the is
of of
the tungsten
filament 8 in
where
is temperature
the emissivity
emissivity
of
tungsten
of Kelvin.
0.35, is
is Stefan-
Stefan-
9
Boltzmann’s
constant
is
the
temperature
of
the
filament
in
Kelvin.
9 , and
Boltzmann’s constant , and is the temperature of the filament in Kelvin.
7”
Tungsten”, ChinaTungsten Online [Online][Date Accessed 15/07/13] URL:
15/07/13] URL:
Tungsten”, ChinaTungsten Online [Online][Date Accessed 15/07/13] URL:
http://www.tungsten.com.cn/
(ChinaTungsten
Online,
1997)
8”
http://www.tungsten.com.cn/
(ChinaTungsten
Online, Accessed
1997)
Emisivity”, Montana State University
[Online][Date
15/07/13] URL:
8”
http://www.coe.montana.edu/me/faculty/sofie/teaching/me360/Pyrometry%20Emissivity%20Notes.pdf
Emisivity”,
Montana
State
University
[Online][Date
Accessed
15/07/13] URL:
8”
Emisivity”, Montana State University [Online][Date Accessed 15/07/13] URL:
(Montana
State University, 2006)
http://www.coe.montana.edu/me/faculty/sofie/teaching/me360/Pyrometry%20Emissivity%20Notes.pdf
http://www.coe.montana.edu/me/faculty/sofie/teaching/me360/Pyrometry%20Emissivity%20Notes.pdf
(Montana
State University, 2006)
9”
(Montana
State University,
2006) Wolfram Research [Online][Date Accessed 14/07/13] URL:
Stefan-Boltzmann
Constant”,
9”
http://scienceworld.wolfram.com/physics/Stefan-BoltzmannConstant.html
(Wolfram
Research,
14/07/13]
URL: 2007)
9” Stefan-Boltzmann Constant”, Wolfram Research [Online][Date Accessed
Stefan-Boltzmann Constant”, Wolfram Research [Online][Date Accessed 14/07/13] URL:
http://scienceworld.wolfram.com/physics/Stefan-BoltzmannConstant.html (Wolfram Research, 2007)
http://scienceworld.wolfram.com/physics/Stefan-BoltzmannConstant.html (Wolfram Research, 2007)
7”
http://www.tungsten.com.cn/
Online,
1997)
Tungsten”, ChinaTungsten (ChinaTungsten
Online [Online][Date
Accessed
7”
38
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