Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Multiple-Choice Questions 19.1-19.4, Problem 19.19
A +6.0 nC charge moves at constant speed of 5.5×104 m/s in the region between two magnets, and experiences a force of 8.5×10–6 N. Calculate (a) the magnitude of the magnetic field
at the location of the charge, and (b) determine
the direction of the magnetic force on the +6.0 nC
charge. Show your work and explain your
reasoning. Solution and grading rubric:
- p:
Correct. Determines magnitude of magnetic field at the location of the charge, where the angle θ between velocity v and the magnetic field B is 45°; and the direction of the force on the moving charge from right-hand rule 1. - r:
Nearly correct, but includes minor math errors. Magnitude incorrect (typically from using θ = 90°); or direction of right-hand rule incorrect. - t:
Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. Magnitude incorrect (typically θ = 90°), and direction of right-hand rule incorrect. - v:
Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. - x:
Implementation of ideas, but credit given for effort rather than merit. - y:
Irrelevant discussion/effectively blank. - z:
Blank.
Sections 30882
Exam code: midterm02w1Ig
p: 10 students
r: 12 students
t: 7 students
v: 4 students
x: 0 students
y: 0 students
z: 0 students
A sample "p" response (from student 7187):
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