A rectangular n-type semiconductor bar of width 4.0 cm (along the -axis) and…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism
Problem
A rectangular n-type semiconductor bar of width 4.0 cm (along the y-axis) and negligible thickness carries a steady conventional current I=3.0A toward the +x direction. A uniform magnetic field of magnitude 0.40T is directed toward the −z direction (into the page). During operation a steady transverse potential difference develops between the long edges of the bar.
(a) Describe the direction of the magnetic force acting on the majority charge carriers inside the bar. Your answer must refer explicitly to the given coordinate axes.
(b) Explain qualitatively how this magnetic force results in an internal electric field and a measurable potential difference between the long edges.
(c) Identify which long edge (the edge at +y or the edge at −y) becomes the higher electric-potential side. Justify your choice with clear physical reasoning that cites the type of charge carrier involved.
(d) The current is now reversed so that it flows toward the −x direction while the magnetic field remains unchanged. State any changes that occur in the magnitude and polarity of the transverse potential difference and explain your answer.