Physics quiz question: electron charge transfer

Physics 205B Quiz 3, spring semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Conceptual Question 16.1, Problem 16.5

A Physics 205B student touches a positively charged metal rod to an isolated, uncharged conducting sphere. As a result electrons are __________ the sphere, such that the sphere becomes __________ charged.
(A) removed from; positively.
(B) removed from; negatively.
(C) added to; positively.
(D) added to; negatively.
(E) neither transferred to/from; neutrally.

Correct answer (highlight to unhide): (A)

Positive charge will be transferred from the metal rod to the initially neutral conducting sphere, evenly distributing between the two objects such that they are both positive. This means that negatively charged electrons were transferred from the conducting sphere (making it positive) to the metal rod (reducing the amount of its positive charge).

Section 31988
Exam code: quiz03f1Lm
(A) : 7 students
(B) : 0 students
(C) : 1 student
(D) : 3 students
(E) : 0 students

Success level: 63%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.33