As frequency is given i.e. 100 Hz
So, T = 1/100 S
At T/2 flux linked with coil changes from BA to zero.
B = 0.001 T
Induced emf = Change in flux / time = BA/(T/2) = 2BA/T
2 x 0.001 x π x (1)2 / (1/100) = 0.2π V
Using Maxwell equation, electric field along the circle is
V=∫E.dl=-dФ/dt = AdB/dt
E = 1/(2πr) x e = 0.2π/(2πx1) = 0.1 V/m
I think 0.1 V/m is the correct answer.