Question

Q7. A charge distribution in free space has volume charge density r(4 cos’e) nC/mº for Osrs 20 m and zero otherwise. Determine the electric filed intensity at r = 15m.

Answer 1

The Electric field intensity can be found by using Gauss's Law(Maxwell's First equation) which is given as follows:

∯D.dS = ∫∫∫ρvdV

D= Electric Flux density

ρv=Volume charge density

Here surface S is the suitable Gaussian surface and in case of spherical coordinates most suitable Gaussian surface is a sphere.

Solution is given in the image attached.

Note: E= Electric field intensity

ε∘= Permittivity of free space

8. Iz = x²doo EL 11 - (1) 3 - 2 / 2 lut value of Is sIz & Iz in ean. I Exar arx (²2) x 10 9 4 Put r= 15 and R=20 E(.) [47 (203)] = (15)" x 9 + (-3) x169 4 => E= - 10,55 Eo x 10 9 -19 {o= 8,85 4 x 10 F/m => E= - 10,55 x 10 v/m 8,854 x 10-12 = -1,12 kvm