An insulating thin rod of length l has a linear charge density on it

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

Problem

An insulating thin rod of length l has a linear charge density

\rho(x) = \rho_0 \frac{x}{l}

on it. The rod is rotated about an axis passing through the origin (

x=0

) and perpendicular to the rod. If the rod makes n rotations per second, then the time averaged magnetic moment of the rod is: (1)

\pi n \rho l^3

(2)

\frac{\pi}{3} n \rho l^3

(3)

\frac{\pi}{4} n \rho l^3

(4)

n \rho l^3