Two long cylinders of radii 5 cm and 10 cm form a coaxial cylindrical capacitor, the space between them being filled with a dielectric of relative permittivity 6. The inner cylinder carries a charge of 10-8 C m-1 of its length. Calculate:-

(a) the value of the electric displacement, field strength, and the polarisation at a

point mid-way between the plates;

(b) the potential difference between the plates;

(c) the densities of the surface charges of the dielectric;

(d) the energy associated with the dielectric in one metre of the capacitor.