Show that in empty space, you can get electromagnetic waves. Start by writing down Maxwell's equations for empty space, where there are no currents or charges (p=0,j=0). Then show that you can derive wave equations from these empty space Maxwell's equations. That is, you should get: (del)^2E=(1/(c^2))(2nd derivative with respect to t of E) and (del)^2B=(1/(c^2))(2nd derivative with respect to t of B)
Find out what c is in terms of Î knot and m knot. Hint: to begin, operate on one of Maxwell’s equations with either del, del (dot), or del X. Then use the table of vector identities involving del. Del = upside-down triangle (operator)
Now since empty space is an isotropic medium.
Now use to obtain
May 3rd 2008, 08:14 PM
Originally Posted by nairbdm
thanks thats a big help, but how would you prove that (del)^2B=(1/(c^2))(2nd derivative with respect to t of B) in empty space.
Note that the equations are symmetric in E and -B. You can derive it similarly.