- #1
izzmach
- 7
- 0
Surface current density, K is defined as:
K = σv
where σ is surface charge density and v is velocity.
Given a uniformly charged spherical shell with radius R, spinning at constant angular velocity ω, find the current.
So, I start with this formula:
dI = K dl
dI = σ Rω dl
and I placed the spherical shell at cartesian coordinate with its center at origin and try to solve the question in spherical coordinate.
What path should I take to express dl? Professor explained, dl = R dθ. What I don't understand is, why do we have to take R? Why not R sin(θ)?
K = σv
where σ is surface charge density and v is velocity.
Given a uniformly charged spherical shell with radius R, spinning at constant angular velocity ω, find the current.
So, I start with this formula:
dI = K dl
dI = σ Rω dl
and I placed the spherical shell at cartesian coordinate with its center at origin and try to solve the question in spherical coordinate.
What path should I take to express dl? Professor explained, dl = R dθ. What I don't understand is, why do we have to take R? Why not R sin(θ)?