PASCO TD-8555 THERMAL RADIATION SYSTEM - Manual (Page 13)

9
012-04695D Thermal Radiation System
Experiment 2: Inverse Square Law
EQUIPMENT NEEDED:
— Radiation Sensor
— Stefan-Boltzmann Lamp, Millivoltmeter
— Power Supply (12 VDC; 3 A), meter stick.
Align axes of filament and Sensor
Top View
X
Millivoltmeter
Meter Stick
Align zero-point of meter stick
with center of filament
Power Supply
(13 V MAX!)
Figure 2.1 Equipment Setup
① Set up the equipment as shown in Figure 2.1.
a. Tape a meter stick to the table.
b. Place the Stefan-Boltzmann Lamp at one end of the meter stick as shown. The zero-
point of the meter stick should align with the center of the lamp filament.
c. Adjust the height of the Radiation Sensor so it is at the same level as the filament of the
Stefan-Boltzmann Lamp.
d. Align the lamp and sensor so that, as you slide the Sensor along the meter stick, the axis
of the lamp aligns as closely as possible with the axis of the Sensor.
e. Connect the Sensor to the millivoltmeter and the lamp to the power supply as indicated
in the figure.
② With the lamp OFF, slide the sensor along the meter stick. Record the reading of the
millivolt-meter at 10 cm intervals. Record your values in Table 2.1 on the following page.
Average these values to determine the ambient level of thermal radiation. You will need to
subtract this average ambient value from your measurements with the lamp on, in order to
determine the contribution from the lamp alone.
③ Turn on the power supply to illuminate the lamp. Set the voltage to approximately 10 V.