A student measures the radiant power per unit area emitted by a lamp filament at…
MATHEMATICS · Subjective · A Level · Mathematics · Data presentation and interpretation · Data presentation and interpretation
Problem
A student measures the radiant power per unit area R emitted by a lamp filament at various steady temperatures. The data obtained are:
Temperature T (K): 900, 1000, 1100, 1200, 1300
Measured R (kW\,m−2): 38, 56, 83, 118, 150
(i) Compute T4 for each temperature and list the corresponding pairs (T4,R).
(ii) On a graph sheet, plot R (vertical axis) against T4 (horizontal axis). Draw the best-fit straight line through the plotted points.
(iii) From the slope of your straight line, determine a numerical value of the constant relating R and T4. Express your result in SI units.
(iv) Compare the constant obtained in part (iii) with the accepted value 5.67×10−8Wm−2K−4. Calculate the percentage difference and comment briefly on whether the measurements support the expected temperature dependence of radiant power.
(v) Identify any two data points that deviate noticeably from the straight line and suggest one plausible experimental reason for each deviation.