Radiation from an accelerated point charge Debapriyo Syam 1 , Kolahal Bhattacharya 2 1 Guest Faculty Member, Centre for Astroparticle Physics and Space Science, Bose Institute, Kolkata (IN) 2 Homi Bhabha Centre for Science Education (TIFR), Mumbai (IN) Abstract In this short communication we present an elementary derivation of the Larmor’s formula of radiation from a point charge, based largely on geometrical arguments. This proof is originally due to Thomson more than one hundred years ago [1]. Whereas the standard texts (e.g.[2]) present the topic from a vector-algebra standpoint, this derivation is physically intuitive. Consider the motion of a particle of charge q. See Fig. 1. Fig. 1 The velocity v  of the particle may vary in an arbitrary manner. The electric and magnetic fields due to the particle can be calculated from the retarded potentials originally obtained by Lienard and Wiechert. The Lienard-Wiechert potentials:             Rc v R R q t r V    1 4 1 ) , ( 0  ) , ( 1 4 ) , ( 2 0 t r V c v Rc v R R v q t r A                        Here v  is the velocity of the charge at the retarded time (t – R /c) and R  is the vector from the retarded position to the field point given by the vector r  . See Fig. 1. When v/c → 0, the present position of the particle nearly coincides with its retarded position; R q t r V   0 4 1 ) , (   R v q t r A        4 ) , ( 0