The intensity of radiation from an electric dipole is proportional to (sin 2 )/r 2 , where

The intensity of radiation from an electric dipole is proportional to (sin² θ)/r², where θ is the angle between the electric dipole moment and the position vector r. A radiating electric dipole lies along the z axis (its dipole moment is in the z direction). Let I₁ be the intensity of the radiation at a distance r = 10 m and at angle θ = 90^o. Find the intensity (in terms of I₁) at

(a) r = 30 m, θ = 90º;

(b) r = 10 m, θ = 45º; and

(c) r = 20 m, θ = 30º.