RRB ALP GK Questions 2026

The medulla oblongata is the breathing centre of the brain, which is why we keep breathing even while asleep. It is the lowest part of the hindbrain and joins the brain to the spinal cord.

Washing soda is sodium carbonate decahydrate: each unit of sodium carbonate holds ten molecules of water of crystallisation. It is made from common salt in steps: baking soda is heated to get anhydrous sodium carbonate, called soda ash, which is then recrystallised from water to give washing soda crystals.

Red has the longest wavelength in visible light, about 700 nm, so the tiny particles of air, fog, smoke and dust scatter it the least.

The reactivity series lists metals from the most reactive to the least reactive, and potassium heads it because it loses its single outer electron most easily.

It gives the direction of the force, and so of the motion, on a current-carrying conductor placed in a magnetic field, which is exactly what turns the coil of a motor.

Combustion means burning in oxygen, and complete burning of methane gives carbon dioxide, water, heat and light. The equation is balanced: one carbon, four hydrogen and four oxygen atoms on each side.

The N shell is the fourth shell (n = 4), and the most electrons a shell can hold is given by the formula 2n², so 2 × 4² = 32.

In diamond every carbon atom is joined to four other carbon atoms by strong covalent bonds. These bonds point towards the corners of a tetrahedron and build a rigid three-dimensional network that runs through the whole crystal.

It is the standard set of rules used for reflection by spherical mirrors and for the mirror formula. Under this convention the pole of the mirror is the origin and the principal axis is the x-axis.

Magnification is a ratio of two lengths, so the units cancel and it is a pure number. For a mirror or a lens, magnification m equals the height of the image divided by the height of the object (h′/h).

A ray that passes through the optical centre of a thin lens comes out in the same direction, without any bending.

Red cabbage is a natural acid-base indicator, methyl orange is a synthetic acid-base indicator, and onion and clove are olfactory indicators.

The d-block occupies the middle of the modern periodic table, groups 3 to 12, and its members are also called transition elements.

A red blood cell is a biconcave disc, thin in the middle and thick at the edge, not an amoeboid cell.

Mercury (Hg) belongs to group 12, not group 11. Group 11 of the modern periodic table holds copper (Cu, atomic number 29), silver (Ag, 47) and gold (Au, 79).

Platelets are the tiny cell fragments that rush to a cut and start the clot. They are also called thrombocytes and are made in the bone marrow from large cells called megakaryocytes.

One ampere is the current that flows when one coulomb of charge passes a point in a circuit in one second.

This is Kirchhoff's first law, the current law or junction rule, which he stated in 1845. It says the total current entering a junction equals the total current leaving it, because charge cannot pile up or vanish at a point.

Roasting means heating a sulphide ore strongly in plenty of air, so that the sulphide turns into an oxide and the sulphur escapes as sulphur dioxide gas.

For a lens, magnification m is the image height divided by the object height, which also equals v divided by u. A plus sign means the image is erect and virtual, and a value of 2 means it is twice as tall as the object.