## 20120428

### Physics quiz question: direction of moving rod

Physics 205B Quiz 6, spring semester 2012
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 20.1

A conducting rod moves at a constant speed through a uniform magnetic field. The top end of the rod is at a higher potential than the bottom end, while the rod is moving:
(A) up ↑.
(B) down ↓.
(C) left ←.
(D) right →.
(E) into the page ⊗.
(F) out of the page ⊙.
(G) (More than one of these choices is possible.)

Correct answer (highlight to unhide): (F)

With the magnetic force pointing up in the plane of this page, and magnetic field lines pointing to the right in the plane of this page, from applying the appropriate right hand rule, velocity of the rod must be coming out of the page.

Section 30882
Exam code: quiz06LR1r
(A) : 4 students
(B) : 0 students
(C) : 0 students
(D) : 3 students
(E) : 3 students
(F) : 17 students
(G) : 0 students

Success level: 63%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.88