RRB Group D GK Questions 2026

Bats send out ultrasonic squeaks and listen for the echoes to locate obstacles and prey. This method is called echolocation.

A rainbow forms when raindrops split white sunlight into its seven colours. When sunlight enters a raindrop, it is refracted, and because each colour bends by a different amount, the colours spread apart.

Washing soda is the crystalline form of sodium carbonate, Na2CO3·10H2O, sodium carbonate decahydrate. Sodium carbonate is made from common salt by the Solvay (ammonia-soda) process.

The Guwahati fair was described as the second event in the Shilp Samagam series for the financial year 2026-27, following the opening edition at Mysuru in Karnataka, which concluded on 19 October.

BHARAT-TULIP was a key focus of the Shilp Samagam Mela held at Guwahati, and its work is to open market access for artisans through physical outlets as well as e-commerce platforms, so that inherited skills reach the channels where buyers shop today.

The fair is organised by that Ministry to give traditional craftspeople a platform to display their heritage, build direct links with customers and strengthen their socio-economic self-reliance.

It is caused by the bacterium Vibrio cholerae, which spreads through food and water polluted with human faeces. The bacterium was identified by Robert Koch in 1883.

Hair turns grey because the chemical make-up of the hair changes as the body stops producing the pigment melanin, so new substances form and the change cannot be reversed.

Lysosomes are small membrane-bound sacs full of hydrolytic enzymes that digest worn-out parts and foreign material inside the cell. Lysosomes are formed from the Golgi apparatus and were discovered by Christian de Duve.

The resistance of a conductor depends on its material and shape, not on how much current flows through it. For a cylindrical conductor, R = ρL/A, where ρ is the resistivity of the material, L the length and A the area of cross-section.

Oxygen makes up about 21 per cent of dry air by volume, second only to nitrogen. Dry air near the ground is about 78 per cent nitrogen, 21 per cent oxygen and 0.93 per cent argon, which is the third most abundant gas.

The enzyme breaks the β-lactam ring that gives penicillin its power. Penicillin was discovered by Alexander Fleming in 1928 from the mould Penicillium notatum.

In an insulator the electrons are tightly bound to their atoms, so there are almost no free electrons to carry a current.

Zinc gives up electrons more readily than iron, so it corrodes first and keeps the iron safe. Coating iron or steel with a thin layer of zinc is called galvanisation.

An ECG records the electrical signals that make the heart muscle contract with each beat. Each heartbeat starts at the sino-atrial (SA) node, the natural pacemaker in the right atrium.

An echo is sound that bounces back from a hard surface such as a wall, cliff or hill and reaches our ears again.

Both stress and pressure are force per unit area, so both are measured in newton per square metre, or pascal (Pa).

A step-up transformer raises an alternating voltage, using more turns in its secondary coil than in its primary. A transformer works on electromagnetic induction and only with alternating current.

For an object between F and P, the image forms behind the mirror, not at infinity. When an object is placed between the pole and the principal focus of a concave mirror, the reflected rays spread out and never meet in front of the mirror.

It comes from the rise and fall of sea tides, a renewable source that is not among the traditional fuels.