Hollow Sphere with Uniform Surface charge

[woprxcpe1704tks]

Homework Statement

[/B]

Homework Equations

Poynting's Theorem S = 1/μ₀ (E x B)
Momentum = p = μ₀ε₀ ∫ S dτ

The Attempt at a Solution

My strategy was to treat the hollow sphere as a point charge (by Gauss' Law), so E = 1/4πε₀ Q/a². I believe the magnetic field would be B = 2/3μ₀M (where M is the magnetic dipole moment per unit volume). For part A, would this be the correct total electromagnetic momentum if I used the formula stated above and the relevant E and B fields. Also, do I have the E and B field formula's correct?

 

[woprxcpe1704tks]

Homework Statement

View attachment 95437 [/B]

Homework Equations

Poynting's Theorem S = 1/μ₀ (E x B)
Momentum = p = μ₀ε₀ ∫ S dτ

The Attempt at a Solution

My strategy was to treat the hollow sphere as a point charge (by Gauss' Law), so E = 1/4πε₀ Q/a². I believe the magnetic field would be B = 2/3μ₀M (where M is the magnetic dipole moment per unit volume). For part A, would this be the correct total electromagnetic momentum if I used the formula stated above and the relevant E and B fields. Also, do I have the E and B field formula's correct?

The attachment is my current attempt at part A