RRB Group D GK Questions 2026

An object floats when its average density is less than that of the liquid and sinks when it is greater.

Specific heat is a property of the material, not of the size or shape of the particular body. It is the amount of heat needed to raise the temperature of unit mass (1 kg or 1 g) of a substance by one degree.

X-rays have wavelengths of roughly 0.01 to 10 nanometres, and a typical value is about one ångström (1 Å = 10⁻¹⁰ m = 0.1 nm).

Ice is simply water in its solid state, a single compound with the fixed formula H2O, so it is a pure substance, not a mixture.

Vegetable oils are hardened into margarine and vanaspati ghee by hydrogenation. Liquid vegetable oils are unsaturated: their fatty-acid chains contain carbon-carbon double bonds.

This matches the reactivity series, which lists metals from the most to the least reactive. Sodium is near the top: it reacts violently with cold water and is stored under kerosene.

Temporary hardness is caused by the bicarbonates (hydrogencarbonates) of calcium and magnesium dissolved in water. It is called temporary because it can be removed simply by boiling: on heating, the soluble bicarbonates break down into insoluble carbonates, or magnesium hydroxide, which settle out, and carbon dioxide escapes.

Quick lime is calcium oxide (CaO), which contains no carbonate, so it gives no carbon dioxide with an acid. Acids release carbon dioxide only from carbonates and hydrogencarbonates: the general reaction is metal carbonate plus acid gives salt, water and carbon dioxide.

Plaster of Paris is made from gypsum, not from common salt. When gypsum, calcium sulphate dihydrate (CaSO4·2H2O), is heated to about 373 K, it loses part of its water and becomes calcium sulphate hemihydrate (CaSO4·½H2O), which is Plaster of Paris; it sets hard again when mixed with water and is…

Anthracene sublimes on heating, while common salt does not, so heating the mixture separates them. Sublimation is the change of a solid directly into vapour without passing through the liquid state.

A honeybee sting injects methanoic acid, also called formic acid (HCOOH), which causes the burning pain and irritation.

Potassium hydroxide gives potassium soaps, which are softer and milder than sodium soaps. Saponification is the reaction in which an oil or fat is heated with an alkali to give soap, the sodium or potassium salt of a long-chain fatty acid, and glycerol.

Rain water is the purest natural form of water because it is formed by evaporation and condensation, a natural distillation.

Its Pink Patrol initiative, with the tagline Eyes in the Sky, SHAKTI on the Ground, is a women-led model that combines drone-assisted surveillance with rapid-response teams working under the SHAKTI framework.

The correct answer is Sonali Mishra, Director General of the Railway Protection Force, who presided over the high-level conference and closed it by stressing the need for intelligence-led policing to strengthen railway security.

The 8th All India Conference of Government Railway Police Chiefs, convened by the Railway Protection Force, concluded in New Delhi on 23 October 2026.

Adipose tissue is a loose connective tissue whose cells, called adipocytes, are built to store fat. Each cell holds a large droplet of fat that pushes the nucleus and cytoplasm to one side.

Temporary hardness is caused by the bicarbonates of magnesium and calcium, Mg(HCO3)2 and Ca(HCO3)2. It is called temporary because simple boiling removes it: on heating, the soluble bicarbonates break down into insoluble carbonate or hydroxide, carbon dioxide and water, and the solid settles out.

Born at Kudki in the Merta country of the Rathores and married to a prince of Mewar, she turned away from the life of the palace to the worship of Krishna, whom she called Giridhar Gopal, kept the company of wandering saints against the wishes of her husband's family, and…

Deshnoke stands on the Bikaner to Nagaur road in Bikaner district, and the temple of Karni Mata there is known across the world for the thousands of rats, called kabas, that live in it and are fed by the worshippers.