RRB Group D GK Questions 2026

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…

In every real machine some of the work put in is used in overcoming friction between the moving parts and in lifting the parts of the machine itself, and that work leaves the system as heat and sound, so the work delivered to the load is always less than the…

A wedge is two inclined planes joined back to back, and an axe, a knife, a chisel and a nail all work on that principle: a force applied at the blunt end is turned into a much larger sideways force at the sharp edge, and the thinner and longer the…

The pitch of a screw is the distance between two consecutive threads measured along its axis, and it is also the distance through which the screw advances in one complete turn; the velocity ratio of a screw is the circumference of the circle described by the handle divided by the…

The velocity ratio of an inclined plane is the length of the slope divided by its vertical height, because the load is pushed along the whole slope while it is raised only through the height; here ten divided by two gives five, so in the ideal case an effort of…

In a single fixed pulley the rope that is pulled down moves exactly as far as the load rises, so the distance moved by the effort equals the distance moved by the load and the velocity ratio is one; the pulley gives no gain in force and is used only…