Railway GK Questions 2026

A piedmont plateau lies at the foot of a mountain range with a plain or the sea on its other side, and it is usually lower than an intermontane plateau; Patagonia lies between the Andes and the Atlantic, and the Piedmont plateau of the United States between the Appalachians and…

A peneplain, meaning almost a plain, is the end stage of the normal cycle of river erosion in a humid region, when valleys have widened and divides have been worn down until the land lies close to base level, with a few resistant residual hills standing above it.

Khadar is the low-lying newer alluvium that the rivers flood and renew nearly every year, so it is free of lime nodules, rich in fine silt and the most productive land of the plain; in Punjab the Khadar strip along a river is called Bet.

The Bhabar is a narrow belt of eight to sixteen kilometres along the foot of the Shiwaliks, laid with pebbles and gravel brought down by the rivers; it is so permeable that the smaller streams sink into it and vanish.

The Deccan Trap was built by fissure eruptions of highly fluid basalt lava towards the close of the Cretaceous period, which spread as sheet after sheet over a vast area of western and central India; the weathering of that basalt gives the black cotton soil, also called regur.

Lying between the Himalayas on the south and the Kunlun on the north, it is an intermontane plateau, the highest and the largest in the world, with an average elevation of about four and a half thousand metres, which is why it is called the Roof of the World.

Kilimanjaro in Tanzania is a dormant volcano built up by repeated eruptions of lava and ash around its vents, and at 5,895 metres it is the highest point in Africa.

Block mountains are formed by tensional forces that break the crust along faults; the block left standing between or beside the faults is called a horst and the sunken trough is a graben or rift valley.

The Aravalli range of Rajasthan and Haryana is an old or relict fold mountain, folded in the Precambrian era and worn down by erosion to low, rounded hills; Guru Shikhar on Mount Abu is its highest point.

A water molecule has two hydrogen atoms of atomic mass one and one oxygen atom of atomic mass sixteen, so the masses are two and sixteen, which is a ratio of one to eight; this fixed ratio in every sample of water, whatever its source, is the classic illustration of…

Cholera is caused by the bacterium Vibrio cholerae and spreads through water and food contaminated with faecal matter, which is why it breaks out after floods and wherever sewage mixes with the water supply; typhoid, hepatitis A, dysentery and polio spread the same way.

Soap is the sodium or potassium salt of a long chain fatty acid.

A moderator slows down the fast neutrons released by fission so that they can cause further fission, and heavy water is the best of them because it slows neutrons well while absorbing very few; in Indian pressurised heavy water reactors it also serves as the coolant that carries heat away…

In reverse osmosis the water is pushed through a semi-permeable membrane at a pressure greater than its osmotic pressure, so the flow runs opposite to natural osmosis; the membrane lets water molecules through and holds back dissolved salts, heavy metals and most microbes, which is why reverse osmosis is also…

Bleaching powder is prepared by passing chlorine over dry slaked lime and is written as calcium oxychloride; in water it releases chlorine, which kills bacteria and other pathogens, and that is why it is used both for disinfecting water supplies and for bleaching cloth and paper.

Alum, that is aluminium sulphate or potash alum, is a coagulant: in water it forms a gelatinous hydroxide that gathers the fine clay and colloidal particles into heavier flocs, which then settle in the sedimentation tank and are removed, leaving clear water for filtration.

Water contracts as it is cooled to four degrees, is densest at that temperature, and then expands again as it cools further to zero, which is called the anomalous expansion of water.

These bicarbonates are formed when water containing dissolved carbon dioxide passes over limestone, and they are unstable; on boiling they lose carbon dioxide and settle as insoluble carbonates, which is why this kind of hardness is called temporary and can be removed by boiling alone, or by the Clark method…

Heavy water is D2O, in which both hydrogen atoms are deuterium, the isotope whose nucleus has one proton and one neutron, so its molecular mass is twenty instead of eighteen.

In an ion exchange plant the water passes through a cation resin, which takes up the calcium and magnesium ions, and then through an anion resin, which takes up the sulphate, chloride and bicarbonate ions; because the hardness-causing ions are actually taken out of the water, the hardness can be…