Question R13 Q17 - MIT Science Bowl Invitational 2020

Which of the following gives the best definition for stellar opacity for a certain material?

W) The fraction of photons passing through which are absorbed or scattered

X) The change in visual apparent magnitude as a result of light passing through

Y) The cross-sectional area of absorption and scattering of light passing through, per unit mass

Z) The inverse of the mean free path of light passing through

Science Bowl Question