Problem 3.24

The electric field strength depends only on the \(x\) and \(y\) coordinates according to the law \(\mathbf{E}=a(x \mathbf{i}+y \mathbf{j}) /\left(x^{2}+y^{2}\right),\) where \(a\) is a constant, \(\mathbf{i}\) and \(\mathbf{j}\) are the unit vectors of the \(x\) and \(y\) axes. Find the flux of the vector \(\mathbf{E}\) through a sphere of radius \(R\) with its centre at the origin of coordinates.