Please explain the concept

Q85. A particle with charge -q moves with a uniform angular velocity o in a circular orbit of radius a in the xy- plane, around a fixed charge +q, which is at the centre of the orbit at (0,0,0). Let the intensity of radiation at the point (0,0,R) be 7, and at (2R,0,0) be '1, The ratio2 for Ra, is (a) 4 (b)- (d) 8 8