Defence GK Questions 2026

Buddhist texts list sixteen mahajanapadas of the sixth century BCE, and Gandhara, in the north-west covering the Peshawar and Rawalpindi region, had its capital at Taxila (Takshashila), near present-day Islamabad in Pakistan.

Starlight has to cross many layers of air before it reaches the eye, and these layers keep changing in temperature and density, so their refractive index keeps changing too.

Isaac Newton built the first practical reflecting telescope in 1668. In it, light from the star falls on a large concave mirror at the bottom of the tube, and a small flat mirror set at 45 degrees near the top turns the light sideways to the eyepiece.

Levers are grouped by where the fulcrum, the load and the effort sit. In a second class lever the load lies between the fulcrum and the effort.

Each human kidney has about one million nephrons, and every nephron begins with a cup-shaped Bowman's capsule that encloses a knot of capillaries called the glomerulus.

Vitamin D helps the intestine absorb calcium and phosphorus, so without it the bones of a growing child stay soft and bend, giving bow legs, a pigeon chest and a large forehead; this disease is rickets.

LIGO, the Laser Interferometer Gravitational-Wave Observatory in the USA, detected gravitational waves for the first time in September 2015 (announced in February 2016), and such waves were predicted by Einstein's general theory of relativity in 1916.

Milk of magnesia is a white suspension of magnesium hydroxide, Mg(OH)2, in water, and its milky look gives it the name.

Galvanisation is the coating of iron or steel with a thin layer of zinc so that the iron underneath does not rust.

The name of a rowing event tells you both the size of the crew and the way the oars are held: sculling means each rower works a pair of oars, and double means the boat carries two of them.

What the Prime Minister called noteworthy was not the single silver alone but the run behind it: medals at three Asian Games one after another, a record of turning up at the top of the sport over many years rather than in one good season.

Sanda is the full-contact fighting format of wushu and its bouts are decided in weight categories, which is why the weight appears in the name of the event itself.

A lactometer floats in milk and shows its relative density. Pure milk is denser than water, so adding water lowers the density and the instrument sinks deeper, which reveals the adulteration.

The horsepower is an older practical unit of power that survives in the rating of engines, pumps and motors, and it equals about 746 watts.

The mole is the chemist's counting unit: one mole of any substance contains the Avogadro number of particles, about six followed by twenty-three zeros, whether those particles are atoms, molecules or ions.

A barometer measures the pressure of the atmosphere, traditionally by balancing it against a column of mercury. It is also used for forecasting weather, because a sudden drop in pressure signals an approaching storm, and for finding altitude, since pressure falls as one rises.

Work is force multiplied by displacement. Force has the dimensions M L T⁻², and multiplying it by a length adds one more power of L, which gives M L² T⁻².

Pressure is force divided by area, so its unit is one newton per square metre, which is given the name pascal after Blaise Pascal.

A light year is the distance that light, moving at about three lakh kilometres per second, covers in one year, which works out to roughly 9.46 trillion kilometres.

The candela takes its name from the candle, which was once used as a rough standard of light, and it is one of the seven base units of the SI system.