The Aryabhata spacecraft, named after the famous Indian astronomer, was India's first satellite; it was completely designed and fabricated in India and launched by a Soviet Kosmos-3M rocket from Kapustin Yar on April 19, 1975.

At high temperatures, the tungsten filament gets hot and atoms in the filament vibrate more. The electrons in the current now collide more with the atoms & more energy is needed to push the current through the filament. Hence, the resistance of tungsten increases with temperature.

Whereas oxygen, nitrogen, and argon are not examples of greenhouse gases.

The tendency nowadays is to use synduction or synchronous motors. The synduction motor resembles an induction motor but runs at synchronous speed.

Ecology is the study of the relationships between living organisms, including humans and their physical environment. The German scientist Earnst Haeckel was the first to use this word in 1869.

Acetylene is the only fuel gas suitable for gas welding because of its favourable flame characteristics of both high temperature and high propagation rates. Other fuel gases, such as propane, propylene or natural gas, produce insufficient heat input for welding but are used for cutting, torch brazing and soldering.