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| -rw-r--r-- | blackbody.tex | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/blackbody.tex b/blackbody.tex index cc2d530..aad3dd8 100644 --- a/blackbody.tex +++ b/blackbody.tex @@ -188,14 +188,22 @@ Lamp, Power supply. % Resistance of filament (room temperature)=&$\underline{\hskip .7in}$ %\end{tabular} -\item Set up the equipment as shown in -Fig. \ref{bbht}. VERY IMPORTANT: make all connections to the lamp when the -power is off. Turn the power off before changing/removing connections. The -voltmeter should be directly connected to the binding posts of the -Stefan-Boltzmann lamp. Compare readings provided by the power supply and the -multimeter. Which one is the correct one? Think about your measurement -uncertainties. -% +\item connect a multimeter as voltmeter to the output of the power supply. + {\bf Important:} make sure it in the {\bf voltmeter mode}. + Compare voltage readings provided by the power supply and the multimeter. + Which one is the correct one? Think about your measurement + uncertainties. + +\item Set up the equipment as shown in Fig. \ref{bbht}. VERY IMPORTANT: + make all connections to the lamp when the power is off. Turn the + power off before changing/removing connections. The voltmeter + should be directly connected to the binding posts of the + Stefan-Boltzmann lamp. In this case the multimeter voltmeter has + direct access to the voltage drop across the bulb, while the power + supply voltmeter reads an extra voltage due to finite resistance of + the current meter. Compare readings on the multimeter and the power + supply current meters. Which one is the correct one? Think about + your measurement uncertainties. \item Place the thermal sensor at the same height as the filament, with the front face of the sensor approximately 6 cm away from the filament (this distance will be fixed throughout the measurement). Make sure no other objects are viewed by the sensor other than the lamp. % |