Defence GK Questions 2026

Kalhana composed the Rajatarangini, the river of kings, in Sanskrit verse in the twelfth century. It traces the rulers of Kashmir in sequence, weighs inscriptions, coins and earlier chronicles as evidence, and is therefore usually described as the first work of Indian historical writing in the modern sense.

The Mimamsa Sutra, also called the Purva Mimamsa Sutra, was composed by the sage Jaimini and is the founding text of the Mimamsa school, one of the six orthodox schools of Indian philosophy; it is concerned with the correct interpretation of the ritual portions of the Vedas and with the…

The Kathasaritsagara, whose name means the ocean of the streams of story, was composed in Sanskrit verse in the eleventh century by Somadeva of Kashmir for the queen Suryavati, and it is a vast frame narrative drawing on the lost Brihatkatha of Gunadhya; the Vetala Panchavimshati, known in Hindi as…

The Ashtadhyayi, which means eight chapters, is Panini's grammar of Sanskrit and the oldest surviving grammar of any Indian language; its roughly four thousand rules describe the language with a precision that modern linguists still study.

The Chinese Buddhist monk Hiuen Tsang, whose name is also written Xuanzang, travelled in India during the reign of Harshavardhana in the seventh century, studied at Nalanda and recorded what he saw in the Si-yu-ki, the Records of the Western World, which remains the fullest description of India in that…

Kavirajamarga, written in the ninth century and attributed to the Rashtrakuta king Amoghavarsha the First, is a treatise on poetics and is the earliest surviving literary work in the Kannada language, which is why it is quoted in every question on the beginnings of regional literature.

Abu Rayhan al-Biruni, a Persian scholar from Khwarizm, came to India in the time of Mahmud of Ghazni in the early eleventh century, learnt Sanskrit, read Indian texts in the original and wrote the Kitab-ul-Hind, also called Tahqiq-i-Hind, a study of Indian religion, philosophy, astronomy, law and custom that is…

After the oil shock of 1973 Brazil launched the Proalcool or National Alcohol Programme in 1975, requiring ethanol made from its abundant sugarcane to be blended with petrol and later building cars that could run on pure ethanol; it is the oldest and best known national biofuel programme.

GOBARdhan, which expands to Galvanizing Organic Bio-Agro Resources Dhan, was launched in 2018 by the Department of Drinking Water and Sanitation in the Ministry of Jal Shakti as a part of the rural sanitation mission, because turning dung and farm waste into biogas is both a waste management and a…

The Global Biofuels Alliance was launched in September 2023 during the G20 summit held in New Delhi under India’s presidency, with India, the United States and Brazil among its founding members, the three being the largest producers and users of ethanol.

The Pradhan Mantri JI-VAN Yojana was approved in 2019 to give viability gap funding to commercial and demonstration projects that make ethanol from lignocellulosic biomass such as paddy straw and bagasse, since such advanced plants cost far more than ordinary molasses distilleries.

The National Policy on Biofuels of 2018 had set 2030 as the year for twenty per cent ethanol in petrol; the 2022 amendment brought that forward to the ethanol supply year 2025-26, and also widened the permitted feedstock and allowed the production of biofuels in special economic zones for export.

In this notation the letter E stands for ethanol and the number gives its percentage by volume in the blend, so E20 is one fifth ethanol and four fifths petrol, while E10 is a tenth ethanol and E85 is a high blend meant for flex fuel vehicles.

Jatropha curcas yields a non-edible oil seed, and because India cannot spare edible oil for fuel, the National Policy on Biofuels looks to non-edible oils such as Jatropha and Pongamia pinnata, or karanja, along with used cooking oil and animal tallow, as feedstock for biodiesel.

In transesterification a vegetable oil or animal fat is made to react with methanol or ethanol in the presence of an alkaline catalyst such as potassium hydroxide, giving fatty acid methyl esters, which are biodiesel, and glycerol as the by-product.

Biogas is produced by the anaerobic digestion of organic matter, and methane is its largest component, roughly half to three quarters of the gas by volume; this is what makes biogas combustible.

SATAT stands for Sustainable Alternative Towards Affordable Transportation and was launched in October 2018 by the Ministry of Petroleum and Natural Gas; under it the oil marketing companies invite entrepreneurs to set up compressed bio-gas plants from agricultural residue, cattle dung and municipal waste and offer to buy the gas…

Second generation biofuels are made from lignocellulosic biomass that is not food, such as paddy straw, wheat straw, bagasse, cotton stalk and municipal solid waste; the cellulose must first be broken down into fermentable sugars, which makes the process costlier and earns these fuels the name advanced biofuels.

Ethanol is the two carbon alcohol obtained by the fermentation of sugars by yeast, and it is the alcohol blended into petrol under the Ethanol Blended Petrol programme.

A gram of fat yields about nine kilocalories, more than twice the yield of carbohydrate or protein, because its carbon chains are far less oxidised to begin with; this is also why fat is the body’s store of energy and why fatty food is called energy dense.