RRB Group D GK Questions 2026

An angle of incidence of zero means the ray falls along the normal, that is, perpendicular to the surface. By Snell's law, n₁ sin i = n₂ sin r; if i is zero, sin i is zero, so sin r is also zero and the angle of refraction is zero.

Lime water is a clear solution of calcium hydroxide, Ca(OH)₂. When carbon dioxide is passed through it, insoluble calcium carbonate, CaCO₃, forms as a fine white precipitate, which makes the lime water turn milky.

Bronze is made by mixing copper (Cu) with tin (Sn), usually about nine parts copper to one part tin. Adding tin makes the metal harder, stronger and more resistant to corrosion than pure copper, which is why bronze was used for tools, weapons, bells, coins and statues.

Fungi have no chlorophyll, so they cannot make their own food by photosynthesis.

Sulphur dissolves completely in carbon disulphide, so the two form a true solution, and a solution is a homogeneous mixture.

Light, small and dry pollen is a feature of wind-pollinated plants, not of plants that depend on insects. Insect-pollinated (entomophilous) flowers have to attract a visitor and then make the pollen travel on its body.

Himanshu Nandal finished third in this race, and the Prime Minister pointed out that it was the third bronze medal to his name at this edition of the Games, calling it an impressive performance.

The duo became Asian Para Games champions in the Women’s Doubles SL3-SU5 class, and the Prime Minister said their superb performance had brought great pride to the nation and hoped they would continue to shine on the international stage.

Mona Agarwal won the gold in this shooting event at the Asian Para Games, and her winning performance stood as a new world record as well as a new Asian Para Games record.

The two archers won the men's recurve doubles gold at the Asian Para Games, and the Prime Minister said their performance had brought great pride to the nation.

Haney won the gold in that event and set a new world record in the same competition, an achievement the Prime Minister described as a proud moment for Indian para athletics.

Competing at the Asian Para Games for the first time, Sandeep Kumar won the gold in that sprint and set a new world record, and the medal was counted as India's 100th at these Games, which is why the Prime Minister described it as a proud milestone for the nation.

Ammonium sulphide is an unstable, foul-smelling compound that breaks down to release ammonia and toxic hydrogen sulphide, so it is not used as a fertiliser.

Barley is sown in the cool, dry season after the monsoon and harvested in spring, which makes it a rabi crop in the northern states.

Vegetables and fruits supply most of the vitamins and minerals in a vegetarian diet, which is why they are called protective foods.

Silver bromide is the light-sensitive compound coated on black and white photographic film and paper, because light breaks it down into tiny grains of silver metal.

Speed tells only how fast a body moves, while velocity also tells the direction of motion, and a quantity with both magnitude and direction is a vector.

A hypertonic solution has a higher solute concentration than the cell sap, so water leaves the cells by osmosis and the protoplast shrinks away from the cell wall.

That is false: in a physical change the molecules stay the same, and only their arrangement, state or shape alters.

Cardiac muscle is a muscular tissue, not a connective tissue; it is the striated, branched, involuntary muscle that makes up the wall of the heart and contracts rhythmically for life.