RRB Group D GK Questions 2026

Thrust is a force and impulse is force multiplied by time, so thrust divided by impulse has the unit 1/second (s⁻¹), which is the unit of frequency.

The cochlea of the inner ear changes the pressure variations of sound into electrical (nerve) signals, which the auditory nerve then carries to the brain.

In glass, light of shorter wavelength travels more slowly, so the glass has a higher refractive index for it and bends it more.

A system whose walls let no heat pass in or out is called adiabatic, so any change in its state happens with zero heat exchange (Q = 0).

Apart from the Sun, Proxima Centauri is the star nearest to the Earth, about 4.24 light years away. Proxima Centauri is a small, dim red dwarf in the constellation Centaurus and cannot be seen with the naked eye.

These are the only two elements that are liquid at standard room temperature and pressure: mercury is a metal and bromine is a non-metal.

Sodium carbonate, called washing soda in its hydrated form Na₂CO₃·10H₂O, removes both temporary and permanent hardness of water. Hard water contains dissolved calcium and magnesium salts, which stop soap from lathering.

H₂S is a colourless gas with the familiar smell of rotten eggs, and the human nose can detect it even in very small amounts.

Nylon 6 is made from a single monomer, caprolactam, whose ring opens on heating and joins up into long polyamide chains.

The Swedish chemist Berzelius proposed around 1813–1814 that each element be written with one or two letters taken from its name, the system still used today.

A soda-acid extinguisher holds a solution of sodium hydrogen carbonate (baking soda) and a small bottle of sulphuric acid; when the two mix, carbon dioxide is released.

Nitrogen gas is the element itself in a very stable form, and plants cannot take it up directly from the soil or the air, so it is not used as a fertilizer.

The South Eastern Railway zone has its headquarters at Garden Reach in Kolkata. South Eastern Railway was formed in 1955 from the old Bengal Nagpur Railway, whose head office at Garden Reach it inherited.

All rose plants of one kind belong to a single species, the basic unit of classification. A species is a group of individuals that are alike in their main features and can interbreed in nature to produce fertile offspring.

The English physicist James Prescott Joule showed around 1841 that when a current flows through a conductor, the heat produced is proportional to the square of the current, the resistance of the conductor and the time for which the current flows.

India's first underwater metro tunnel runs beneath the Hooghly river in Kolkata. It is part of the East-West Metro corridor (the Green Line) of Kolkata Metro and joins Howrah on the west bank with Kolkata on the east bank.

As blood flows through the thin-walled capillaries, part of its plasma, with small proteins and some white blood cells, leaks out into the spaces between cells.

Algae are the predominantly aquatic members of the Kingdom Plantae. They are simple, chlorophyll-bearing organisms with a thallus body that is not divided into true roots, stems and leaves.

The human body conducts electricity because its fluids contain dissolved salts that break up into ions, and these ions carry current.

The Kolkata Metro is run by Indian Railways as its own zone, the Metro Railway, with its headquarters in Kolkata.