A research group directs a 0.071 nm X-ray beam at a target containing essentially…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Modern Physics · Modern Physics
Problem
A research group directs a 0.071 nm X-ray beam at a target containing essentially free electrons and measures the wavelength of photons scattered at various angles θ. The collected data are shown.
Angle θ (deg) 0 30 60 90 120
Measured λ′ (nm) 0.0710 0.071326 0.072215 0.073430 0.074645
(a) Identify a pair of variables that, when graphed, should yield a straight line according to the theoretical prediction for Compton scattering. Explain your choice.
(b) Using the data provided, determine the slope of the line that would result from your proposed graph and calculate the experimental value of the constant mech.
(c) Use your experimental value from part (b) along with the accepted values of me and c to compute an experimental estimate of Planck’s constant h. Express your answer in J·s and compare it with the accepted value, commenting on the agreement within experimental uncertainty.
(d) Discuss two plausible sources of systematic error that could account for any discrepancy between the experimental and accepted values of h in this experiment.