Answer:
The magnitude of the electric field is

Step-by-step explanation:
Given that,
Charge

radius r = 3.33 cm
Distance a = 4.20 cm
We need to calculate the distance d
According to figure

We need to calculate the electric field
Using formula of electric field





Put the value into the formula


Hence, The magnitude of the electric field is [tex]17.77\times10^{6}\ N/C[/tex]