Defence GK Questions 2026

Toothpaste is mildly basic so that it can neutralise the acid that causes tooth decay. Bacteria in the mouth break down sugar and food particles left on the teeth and produce acids.

For an ideal gas in a fixed volume at a fixed temperature, pressure is proportional to the number of molecules, so half the molecules give half the pressure.

Both have 10 electrons, the same number as a neon atom, so they are isoelectronic. Isoelectronic species have the same number of electrons.

About an axis through the centre, a solid disc has I = ½MR² while a solid sphere has I = ⅖MR², and ½ is larger than ⅖.

Founded in 1767, the Survey of India is the oldest scientific department of the Government of India. It began under the East India Company, with James Rennell as the first Surveyor General of Bengal.

At this one temperature the Celsius and Fahrenheit scales show the same number. The two scales are linked by F = (9/5)C + 32.

Soil scientists list parent material, topography (relief), climate, biological activity and time as the factors that form soil; where people live is not one of them.

This follows the reactivity series of metals, in which zinc lies above iron, iron above lead and lead above copper.

This is double fertilisation, a feature found only in flowering plants. The pollen tube carries the two male gametes into the embryo sac.

Litmus is a purple dye extracted from certain lichens, such as species of Roccella, and it turns red in acid and blue in base.

This first act of the British Parliament to control the East India Company provided for a Supreme Court of Judicature at Calcutta.

The heat needed to turn unit mass of a liquid into vapour at constant temperature is its specific latent heat of vaporisation.

Average force equals the change in momentum of the coin divided by the time of contact.

Temporary hardness comes from dissolved calcium and magnesium hydrogencarbonates (bicarbonates), and it can be removed simply by boiling. On boiling, calcium hydrogencarbonate breaks down into insoluble calcium carbonate, water and carbon dioxide, and the carbonate settles out; this is the scale seen inside kettles.

At Rudraprayag in Uttarakhand the Mandakini, which flows down from near Kedarnath, joins the Alaknanda. Rudraprayag is one of the Panch Prayag, the five holy confluences of the Alaknanda on its way to forming the Ganga.

The stinging hairs on nettle leaves break on touch and inject methanoic acid, also called formic acid, into the skin, which causes the burning pain.

Outside a long straight wire the field is B = μ₀I/(2πr), so at a fixed distance r it is directly proportional to the current I. Hans Christian Oersted found in 1820 that a current deflects a compass needle, showing that a current produces a magnetic field.

Magnesium does not react with cold water; it reacts with hot water and burns in steam to form magnesium oxide and hydrogen.

With constant acceleration the distance covered is s = ut + ½at², and the first term contains the initial velocity u. This is the second equation of motion.

Denmark is known as the country of winds because strong westerly winds blow across its flat land and long North Sea coast for most of the year.