What is electric field and what does it mean" changing electric field"?

Dear Student,

Electric field is imaginary field created by a charge or system of charges through which it applies force on a unit charge at a point in its field.  A changing electric field makes a magnetic field. These phenomena are expressed mathematically through the Faraday law and the Ampere-Maxwell law:
$$\begin{gathered} \oint \overrightarrow{E}.\overrightarrow{dl}=-\frac{d{\phi }_B}{dt} \\ and \\ \oint \overrightarrow{B.}\overrightarrow{dl}={\mu }_0{\epsilon }_0\frac{d{\phi }_E}{dt} \end{gathered}$$