We know that the relationship between Electric Field , Charge and Distance is given by :
[tex] E=\frac {kQ}{R^2} [/tex]
Where, k[tex]=[/tex] Columb's Constant [tex] =8.99\times 10^9 Nm^2C^-2 [/tex]
Q= Source charge that generates the electric field
R = Distance from the charge =4m
E=Electric field = 1236N/C
As, we have to find the charge therefore rearranging the formula we get :
[tex] Q=\frac {ER^2}{k} [/tex]
Putting the values we get
[tex] Q = \frac {1236\times 4^2}{8.99\times 10^9} [/tex]
On solving
[tex] Q = \frac {2199.77}{10^9} =2.19 \times 10^-6 =2.2[/tex] µC
Therefore the magnitude of source charge is 2.2 µC
