In this undergraduate physics experiment I determined the temperature of a tungsten filament from its electrical resistance and empirically confirmed the Stefan–Boltzmann T4 radiation law. Using a NI ELVIS II+ DAQ and LabVIEW data‑logging, I measured current, voltage, and radiant output while sweeping the supply from 1 V to 12 V. A linear fit of P vs T4 yielded a slope within 1 % of the theoretical constant, validating black‑body radiation theory.
Mapped filament resistance to temperature from 296 K to 15 890 K using measured V‑I curves.
Linear regression on P vs. T4 gave slope 4.103 ± 0.074 (≈ 1 % error).
Identified and corrected typographical error in the lab manual’s power expression.
V (V) I (A) P_rad (mV) R(Ω) T(K)
1.0 0.96 0.682 1.04 322
5.0 1.94 8.646 2.57 3598
12.0 3.06 35.132 3.92 15 891
Fit: ln P = 4.103 ln T – 18.27
R² = 0.997