This is the differential statement of Faraday’s law and it clearly indicates the relation between the electric and magnetic
fields. The electric field is nonconservative (the curl of the electric field intensity is not zero). For this reason, the electric
field intensity cannot be defined as the gradient of a scalar potential and the definition of electrostatic potential cannot be
used here. Equation (10.8) also indicates that Faraday’s law is general and the loop is not necessary for the induced emf to
exist. This aspect of the relation will be used later to define and evaluate induced currents in conducting volumes.