Physics quiz question: least number of significant figures

Physics 205A Quiz 1, fall semester 2013
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Comprehensive Problem 1.63

The measurement with the least number of significant figures is:
(A) 23.4 tons.
(B) 1.55 kg.
(C) 130 lb.
(D) 0.00100 g.
(E) (There is a tie.)

Correct answer (highlight to unhide): (C)

Significant digits are denoted by the digits in green below (and digits in yellow are not significant). Response (A) has three significant figures. Response (B) also has three significant figures. Response (C) has two significant figures, as the trailing zero is ambiguous when there is no explicit decimal point indicated. Response (D) also has three significant figures, as the leading zero to the left of the decimal point is not significant, along with the two placeholder zeroes immediately to the right of the decimal point.
(A) 23.4 tons.
(B) 1.55 kg.
(C) 130 lb.
(D) 0.00100 g.

Sections 70854, 70855, 73320
Exam code: quiz01cH3E
(A) : 2 students
(B) : 1 student
(C) : 51 students
(D) : 4 students
(E) : 18 students

Success level: 67%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.75