A long horizontal conducting rod is pushed at a constant speed of into a region of…

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism

Problem

A long horizontal conducting rod is pushed at a constant speed of

3\,\text{cm s}^{-1}

into a region of uniform magnetic field

0.25\,\text{T}

directed vertically. The current in the rod is

4\,\text{A}

and is along the rod, perpendicular to the field. If the leading end of the rod just enters the field at

t = 0

, what is the magnetic force on the rod at

t = 4\,\text{s}

? (a)

0.24\,\text{N}

(b)

0.12\,\text{N}

(c)

0\,\text{N}

(d)

0.06\,\text{N}