Physics midterm question: comparing indices of refraction

Physics 205B Midterm 1, spring semester 2019
Cuesta College, San Luis Obispo, CA

Light in air with an incident angle of 19.0° is transmitted into acetone at an angle of 13.9°. Light in air with an incident angle of 44.0° is transmitted into turpentine at an angle of 28.2°. Show that the index of refraction of acetone is less than the index of turpentine. Explain your reasoning using the properties of light and refraction.

Solution and grading rubric:

• p:
  Correct. Uses Snell's law to solve for and compare the numerical values for the indices of refraction of acetone versus turpentine.
• r:
  As (p), but argument indirectly, weakly, or only by definition supports the statement to be proven, or has minor inconsistencies or loopholes.
• t:
  Nearly correct, but argument has conceptual errors, or is incomplete.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Some garbled attempt at applying Snell's law, angles, and/or indices of refraction.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. No clear attempt at applying Snell's law, angles, and/or indices of refraction.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.
  

Grading distribution:
Sections 30882, 30883
Exam code: midterm01Ft6G
p: 41 students
r: 0 students
t: 0 students
v: 1 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 1348):