Physics clicker question: significant figures

Physics 5A, Fall Semester 2007
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Chapter 1.4

Students were asked the following clicker question (Classroom Performance System, einstruction.com) near the beginning of their learning cycle:

[0.3 points.] Consider these five length measurements:

(A) 0.00409 m.
(B) 81.602 m.
(C) 1.970 × 10^3 cm.
(D) 80,000 km.
(E) 80,000.0 mm.

Which measurement has the most number of significant figures?

Student responses
Sections 0906, 0907
(A) : 5 students
(B) : 6 students
(C) : 3 students
(D) : 3 students
(E) : 10 students

This question was asked again after displaying the tallied results with the lack of consensus, with the following results. No comments were made by the instructor, as students were able to discuss and determine the correct answer among themselves.

[0.3 points.] Consider these five length measurements:

(A) 0.00409 m.
(B) 81.602 m.
(C) 1.970 × 10^3 cm.
(D) 80,000 km.
(E) 80,000.0 mm.

Which measurement has the most number of significant figures?

Correct answer: (E)

Student responses
Sections 0906, 0907
(A) : 2 students
(B) : 0 students
(C) : 1 student
(D) : 0 students
(E) : 24 students