Hrishikesh Rakshit obtained DSc (1934) from University of Calcutta. He served as Assistant Director, National Physical Laboratory (1948-49); Assistant Professor and Head, Department of Physics and Electronics Communications, Bengal Engineering College, Howrah (1949-55); Senior Professor and Head, Department of Electronics and Electrical Communication Engineering, IIT Kharagpur (1955-56); and UNESCO Expert in Electronics, University of Damascus, Syria (1966-67).
Academic and Research Achievements: Rakshit devised a novel method for measuring field strengths of echoes in ionospheric studies, and recorded wireless echoes with the same antenna for transmission and reception, which provided the basic idea for radar. He developed (i) a noise less recording system, 3-phase R-C oscillator for producing wideband FM, and (ii) a delayed-coincidence technique for (a) measuring ionospheric height, and (b) fabricating an electronic torquemeter with remote control. Professor Rakshit showed that due to dissociation of O2 molecules by the absorption of solar ultraviolet radiations, the density of O2 decreases very rapidly with height above 100 km. On the other hand, the density of O2 which is almost zero at 80 km, increases rapidly with height, attains a maximum at about 105 km and then decreases gradually. The transition layer in which O2 decreases rapidly plays an important role in the production of E-layer.
Awards and Honours: Professor Rakshit was elected Fellow of the National Academy of Sciences (India), Allahabad; Indian Physical Society; Institute of Physics, London; and Institution of Electronics and Telecommunication Engineers (India).