4 electrical & electronics students

 PSLV-C19   India's first indigenously built all-weather Radar Imaging Satellite, RISAT-1, with applications ranging from agriculture to natural disaster management, is now in polar  orbit after its carrier, the PSLV-C19, was launched with clinical precision from the Sriharikota spaceport of the Indian Space Research Organisation (ISRO) on Thursday. RISAT-1, weighing 1,858 kg and the heaviest satellite launched yet by the PSLV, is a state-of-the-art Active Microwave Remote Sensing Satellite carrying a Synthetic Aperture Radar (SAR) that will operate in the C-band. In simpler terms, the RISAT-1 can beam back imaging of the earth surface features at day and night and under all imagined weather conditions. SAR, which gives the RISAT-1 its magical roving eyes, also makes it superior to the generation of optical remote sensing satellites in clearer imaging at all times and under any condition. Terming the PSLV-C19 launch a “grand success,” ISRO Chairman K. Radhak

                    Back-firing If a cathode spot is accidently formed on an anode during the part of the cycle when it is negative to the   cathode , it will lose its valve action and reverse   current will flow. Such a fault is called the arc-back or back-firing.

Infinite bus bar Infinite bus bar  represent a system of large capacity whose frequency and the phase and magnitude of the voltage are not affected even if there is a variation of excitation of a synchronous machine connected to it.

Plugging Plugging means stopping of an electric motor by instantaneous   reversing its torque till it stops.