Robert Cinca - Physics
How I measured the length and uncertainty of the wire
How I measured the length and uncertainty of the wire
To measure the length of the wire, I took the cross-sectional area, rearranged so I
would
get the the
radius,
circumference,
and then area,
multiplied
by the so I
To measure
length worked
of the out
wire, the
I took
the cross-sectional
rearranged
number
of the
turns
in the worked
coil. out the circumference, and then multiplied by the
would get
radius,
number of turns in the coil.
I have measured:
I can
work out that:
have therefore
measured:
I Therefore:
can therefore work out that:
Therefore:
The uncertainty in the length, , is:
(
)
The uncertainty in the length,
My Results
My Results
Number of Turns
Cross-Sectional
Number of Turns Area
Thickness
of Wire
Cross-Sectional
Area
Length
of
Wire
Thickness of Wire
Length of Wire
, is:
(
)
6.5V 0.15A Filament
30±1
6.5V 0.15A
Filament
2
0.005mm
±0.002mm 2
30±1
0.005mm±0.002mm
0.005mm 2 ±0.002mm 2
7.5
mm±.1.8mm
0.005mm±0.002mm 6.5V 0.30A Filament
50±1
6.5V 0.30A
Filament
2
0.024mm
±0.002mm 2
50±1
0.029mm±0.003mm
0.024mm 2 ±0.002mm 2
27mm±2mm
0.029mm±0.003mm
7.5 mm±.1.8mm 27mm±2mm
Figure 14: My findings on the Properties of the Filament Bulbs
Figure 14: My findings on the Properties of the Filament Bulbs
Finding out the how the resistivity of tungsten varies with temperature
Finding out the how the resistivity of tungsten varies with temperature
I researched on the internet how the resistivity of tungsten changes with
5
temperature
I then
plotted the
on a graph
and discovered
quadratic
I researched . on
the internet
how results
the resistivity
of tungsten
changes a with
5 the form
relationship
, where
is the
temperature
. I then plotted the results
on a graph
and
discovered in
a Kelvin,
quadratic and
temperature of
are my thermal
coefficients,
and is just
a constant.
actual quadratic
equation
relationship
of the
form
, where
is the The
temperature
in Kelvin,
and
obtained
from the
graphing of
the resistivity
is:
are
my thermal
coefficients,
and
is just a constant.
The actual quadratic equation .
obtained from the graphing of the resistivity is:
.
Finding out the internal resistance of the PowerPack
Finding out the internal resistance of the PowerPack
In my model, I also needed to work out the internal resistance of the PowerPack. I
6
proceeded
by I setting
up a standard
electrical
circuit resistance
and measuring
different voltage
In my model,
also needed
to work out
the internal
of the PowerPack.
I
6
and current by
readings.
I then
graphed electrical
my results circuit
and worked
out the internal
proceeded
setting up
a standard
and measuring
different voltage
resistance
I calculated
by and
taking
the negative
of the gradient
and
current as
readings. I . then
graphed this
my result
results
worked
out the internal
of the line of
see the this
appendix
for taking
the details
on the tables
resistance
as best fit. Please
. I calculated
result by
the negative
of the and
gradient
graphs.
of
the line of best fit. Please see the appendix for the details on the tables and
graphs.
5
“Resistivity of Tungsten”, The Physics Factbook [Online][Date Accessed 13/06/13] URL:
5
(Elert, Accessed
2004). See appendix
attached tables
http://hypertextbook.com/facts/2004/DeannaStewart.shtml
“Resistivity of Tungsten”, The Physics Factbook [Online][Date
13/06/13] for
URL:
and
graphs.
(Elert, 2004). See appendix for attached tables
http://hypertextbook.com/facts/2004/DeannaStewart.shtml
and
6
graphs.
“EMF and internal resistance”, Teaching Advanced Physics [Online][Date Accessed 18/07/13] URL:
6
http://tap.iop.org/electricity/emf/121/page_46054.html
(Institute [Online][Date
of Physics) Accessed 18/07/13] URL:
“EMF and internal resistance”, Teaching Advanced Physics
http://tap.iop.org/electricity/emf/121/page_46054.html (Institute of Physics)
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