

Electric field intensity (E) at a distance (d) from the centre of a sphere containing net charge q is given by the relation,
E = q /4πε0 d2
Where, q = Net charge
E is electric field =104 N/C
d = Distance from the centre = 1 m
∈0 = Permittivity of free space
1/4πε0= 9 × 109 N m2 C−2
So, net charge on the sphere, q= E(4πε0)d2
q = 104(1)/9 × 109
q = 0.11×10-5 C
Now, Surface charge density of sphere-
σ =q /Surface Area of sphere
Surface Area of sphere, A = 4πr2
Given, radius r of the sphere= 0.25 m
So, Area A =0.785 m2
Surface charge density, σ =q /Surface Area of sphere
= 0.11×10-5 /0.785 = 1.40×10-6
