Answer:
The magnitude of rate of change of electric field is
.
Step-by-step explanation:
Given that,
Radius of the cylindrical region contains a uniform electric field along the cylinder axis, r = 1.2 m
Total displacement current through a cross section of the region,

We need to find the rate of change of electric field. Its is given by the formula as follows :

So, the magnitude of rate of change of electric field is
.