Railway GK Questions 2026

This follows the reactivity series of metals, in which zinc lies above iron, iron above lead and lead above copper.

This is double fertilisation, a feature found only in flowering plants. The pollen tube carries the two male gametes into the embryo sac.

Litmus is a purple dye extracted from certain lichens, such as species of Roccella, and it turns red in acid and blue in base.

The heat needed to turn unit mass of a liquid into vapour at constant temperature is its specific latent heat of vaporisation.

Average force equals the change in momentum of the coin divided by the time of contact.

Temporary hardness comes from dissolved calcium and magnesium hydrogencarbonates (bicarbonates), and it can be removed simply by boiling. On boiling, calcium hydrogencarbonate breaks down into insoluble calcium carbonate, water and carbon dioxide, and the carbonate settles out; this is the scale seen inside kettles.

The stinging hairs on nettle leaves break on touch and inject methanoic acid, also called formic acid, into the skin, which causes the burning pain.

Outside a long straight wire the field is B = μ₀I/(2πr), so at a fixed distance r it is directly proportional to the current I. Hans Christian Oersted found in 1820 that a current deflects a compass needle, showing that a current produces a magnetic field.

Magnesium does not react with cold water; it reacts with hot water and burns in steam to form magnesium oxide and hydrogen.

With constant acceleration the distance covered is s = ut + ½at², and the first term contains the initial velocity u. This is the second equation of motion.

Denmark is known as the country of winds because strong westerly winds blow across its flat land and long North Sea coast for most of the year.

This is absolute zero, more exactly −273.15°C or 0 kelvin, the temperature below which nothing can be cooled. Temperature measures the random motion of particles.

One hertz means one complete cycle per second, so a frequency of 3 Hz means the current completes three full cycles every second.

Pitch is how the ear perceives the frequency of a sound, so a higher pitch means more vibrations per second.

Streptococcus mutans turns dietary sugar, especially sucrose, into a sticky slime that glues it to the teeth. The bacterium makes enzymes called glucosyltransferases that join the glucose units of sucrose into sticky chains called glucans.

These three oxides, made by heating limestone with clay, form the compounds that make cement set and harden. Portland cement was patented by Joseph Aspdin in England in 1824, and named after Portland stone, which the set cement resembled.

The weight we feel is really the push of the floor on us, and in orbit that push disappears. The space station and the astronaut are both in free fall around the Earth.

A thermocouple has no liquid that can freeze, so suitable types can read temperatures far below −200°C. A thermocouple is made of two wires of different metals joined at a junction.

Kepler's third law says the square of a planet's orbital period is proportional to the cube of the semimajor axis of its orbit.

A convex lens forms an image at the same distance as the object only when the object sits at 2f, and here 2f works out to 4R/3.