2013-14.md

course	course_year	question_number	tags	title	year
Electromagnetism	IB	14	IB 2013 Electromagnetism	Paper 2, Section I, D	2013

Use Maxwell's equations to obtain the equation of continuity

$$\frac{\partial \rho}{\partial t}+\nabla \cdot \mathbf{J}=0$$

Show that, for a body made from material of uniform conductivity $\sigma$, the charge density at any fixed internal point decays exponentially in time. If the body is finite and isolated, explain how this result can be consistent with overall charge conservation.