RRB Group D GK Questions 2026

Carbon monoxide binds with haemoglobin far more strongly than oxygen does, so the blood can no longer carry enough oxygen.

The great majority of plant viruses carry their genes as single-stranded RNA. Viruses contain either DNA or RNA, never both, wrapped in a protein coat.

In ecology, a population is defined by three things together: one species, one place and one time. Ecology studies life in levels.

Cyclohexane, C 6 H 12, has 6 C–C single bonds and 12 C–H single bonds, 18 single bonds in all and no double or triple bond.

Silver and copper are the two best conductors of heat among metals. Metals conduct heat because their free electrons carry energy quickly through the solid.

Velocity multiplied by time is displacement, so the area between a velocity-time graph and the time axis gives the displacement.

A bacterium is a prokaryote, so its DNA lies in an irregular region called the nucleoid, with no nuclear membrane around it.

Photo 51 is the X-ray diffraction photograph of DNA that revealed its helical shape. The picture was taken in May 1952 at King's College London by Rosalind Franklin and her student Raymond Gosling.

Twenty crests and twenty troughs make twenty complete waves in 0.1 second, so the frequency is 200 Hz and the wavelength is 330 ÷ 200 = 1.65 m. One complete wave, or one cycle, contains one crest and one trough (for sound, one compression and one rarefaction).

This statement is wrong: the gravitational force between two bodies depends on their masses and on the distance between them.

Three parts of oxygen-16 and one part of oxygen-18 give an average of (3 × 16 + 1 × 18) ÷ 4 = 66 ÷ 4 = 16.5 u. Isotopes are atoms of the same element with the same atomic number but different mass numbers, because they have different numbers…

In boiling, bubbles of vapour form throughout the liquid; in evaporation, only molecules at the surface escape.

Gypsum (calcium sulphate dihydrate) is not a raw material for glass; it is added to cement to slow down its setting.

Bacteria turn the lactose in milk into lactic acid, a new substance, so souring is a chemical change that cannot be reversed.

One kilowatt-hour is the energy used by a 1 kW appliance running for one hour: 1000 W × 3600 s = 3.6 × 10⁶ J. The joule is too small for household bills, so electricity companies charge in kilowatt-hours, commonly called units.

This is the thermite reaction, which is highly exothermic: it gives out so much heat that the iron formed comes out molten.

X-rays have wavelengths from about 0.01 nm to 10 nm, so 1 nm lies well inside the X-ray band. In the electromagnetic spectrum, wavelength decreases from radio waves through microwaves, infrared, visible light and ultraviolet to X-rays and gamma rays.

The element with atomic number 8 is oxygen, which gains two electrons to complete its octet and forms sodium oxide, Na₂O. Oxygen's electrons are arranged as 2, 6, so it needs two more to reach the stable arrangement 2, 8 of neon.

Chemical energy is the energy stored in the bonds that link atoms together in molecules. When a chemical reaction breaks old bonds and forms new ones, this stored energy is released or absorbed.

This statement is wrong: soda glass is the soft glass, while pyrex is a hard borosilicate glass. Ordinary soda-lime glass is made from silica (sand), sodium carbonate and limestone; it softens at a fairly low temperature and is used for windows, bottles and tumblers.