Physics Home > Teaching Labs > Modern Physics > Blackbody Radiation

Topics

Points of Emphasis

Prerequisites

Lab Activities

In this lab, the students measure the temperature dependence at a number of fixed frequencies for a black body. From the data, they are asked to:

a. Plot the data for each wavelength in two ways: I vs T and log I vs 1/T to see how well the data fit the Rayleigh-Jeans formula and Wien's Law respectively.

b. Obtain a value for g = h/k_B.

c. Compare the data to what would be expected from Planck's Law.

d. Check to see if they can distinguish between the three laws and to determine under what circumstances do the R-J or Wien laws provide good description of the data?

Course Level

Intermediate

Student Handouts

Equipment

Number of set-ups available: 1 Per lab station: 1 Thermodyne 47900 furnace/power supply 1 PAR 121 lock-in amplifier 1 set of interference filters in a rotating holder 1 thermocouple detector 1 concave focusing mirror 1 chopper wheel/Bodine Electric Company frequency controller 1 metal platform for chopper wheel, detector and mirror 1 oscillator 4 BNC T-connector 2 BNC to banana (male) adaptors 1 fan (to cool furnance) linear graph paper semilog graph paper covers for windows next to apparatus

Circuit Diagrams

Notes

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