# Assessment Instructions: Problem Set 02 — Optical Depth Attenuation and the Boltzmann Equation for Vega

## Inputs to Inspect
Student submission, this problem set, the solution key, the corresponding lecture slides/notes, and the referenced dataset(s) under `materials/ASTR310/data/`.

## Grading Standard
Award credit for correct method and units first, then for the specific numeric result. A student who shows correct reasoning with a small arithmetic slip should receive most of the available credit; a student with a correct-looking number but no visible derivation steps should not. Because this is a 300-level quantitative course, full marks require a genuine derivation (not just formula substitution) wherever the problem set asks for one.

## Problem-Level Criteria
- Problem 1: 15 points — correct exponential attenuation arithmetic.
- Problem 2: 15 points — correct inversion of the exponential relationship.
- Problem 3: 20 points — correct Boltzmann-ratio arithmetic and computed comparison ratio.
- Problem 4: 15 points — correct quantitative connection and correct identification of the Saha equation.

## Resubmission Policy
Students may resubmit within one week of receiving feedback. A resubmission must show a corrected derivation, not only a corrected final number, and should reference the specific feedback comment it addresses. Regrade to a maximum of 90% of the original point value unless the error was a grading mistake.

## Common Errors to Flag
- Using a linear rather than exponential relationship between transmitted fraction and optical depth.
- Reporting Problem 3 only qualitatively without the required numeric ratio.
- Confusing the Boltzmann equation (excitation) with the Saha equation (ionization) when explaining the missing physics in Problem 4.