NDA GK Questions 2026

Argon is chemically inert, so the hot tungsten filament does not react with it, and its presence also slows the evaporation of tungsten, which is why bulbs are filled with argon, sometimes mixed with nitrogen, instead of being left as a vacuum.

It is called laughing gas because it produces a feeling of elation when inhaled in small quantities, and it is used as a mild anaesthetic in dentistry and minor surgery and as the propellant in whipped cream; it is also a greenhouse gas.

Chlorine released from chlorofluorocarbons destroys ozone fastest where polar stratospheric clouds form in the extreme cold of winter, because those ice clouds hold the chlorine compounds that sunlight then breaks up; the thinning is therefore deepest over Antarctica, where it is called the ozone hole, and is seen over the…

Hydrogen has three isotopes: protium with one proton and no neutron, deuterium with one neutron, which gives heavy water, and tritium with two neutrons, which is radioactive and is used in fusion research and in luminous dials.

A metal more reactive than hydrogen displaces it from a dilute acid, so zinc with dilute sulphuric acid gives zinc sulphate and hydrogen gas, and this is the standard laboratory preparation of the gas; the test is that it burns with a pop.

This is a Directive Principle of State Policy under Article 51, a duty of the State, not a fundamental duty of citizens.

Urine is made in the kidneys, carried down by the ureters, stored in the bladder and passed out through the urethra.

Both articles protect certain laws from being struck down on the ground that they violate Article 14 or Article 19.

Protochordates are marine chordates that have a notochord at some stage but never develop a backbone. The phylum Chordata is split into protochordates and vertebrates.

A mutation is a change in the sequence of the DNA or RNA that carries a virus's genes. A virus is made of genetic material, either DNA or RNA, inside a protein coat.

This body within the Department of Telecommunications is in charge of carrying out the Government's telecom policy. The Telecom Commission was set up in 1989 with administrative and financial powers to deal with all aspects of telecommunications, and in 2018 it was renamed the Digital Communications Commission.

As Chief Justice of India, he set up the Social Justice Bench of the Supreme Court in December 2014.

Microbodies are small vesicles bounded by a single membrane, filled with enzymes that carry out particular metabolic reactions. The main microbodies are peroxisomes and glyoxysomes.

The work done against gravity is mgh = 50 × 10 × 8 = 4,000 J, and doing it in 10 s needs 4,000 ÷ 10 = 400 W. Power is the rate of doing work, P = W/t, and its SI unit is the watt (1 W = 1…

TB spreads through the air when an infected person coughs, sneezes or speaks and others breathe in the tiny droplets carrying the bacteria.

All three statements describe hard water correctly. Statement 1 is correct: temporary hardness comes from dissolved bicarbonates, chiefly calcium bicarbonate (magnesium bicarbonate too).

These are the threshold temperatures the India Meteorological Department (IMD) uses for declaring heat waves and cold waves.

Excess nitrogen fertilizer turns into nitrate, which dissolves easily, seeps down through the soil and contaminates groundwater. Urea and other nitrogen fertilizers are converted by soil bacteria into nitrate ions.

Platinum only gets hot and may glow; it does not react, and on cooling the crucible is exactly as it was, so the change is physical.

For reflection at a plane mirror, the deviation is 180° − 2i, and with i = 40° this gives 180° − 80° = 100°.