Consider a resistor with length L, uniform cross-sectional area

Consider a resistor with length L, uniform cross-sectional area A, and uniform resistivity p that is carrying a current with uniform current density J. Use Eq. (25.18) to find the electrical power dissipated per unit volume, p. Express your result in terms of
(a) E and J;
(b) J and p;
(c) E and p.