RRB NTPC GK Questions 2026

Groundwater drawn through wells and tube wells irrigates the largest part of the net irrigated area of India, and its share has risen steadily since the Green Revolution because a tube well gives water on demand, close to the field and without waiting for a canal turn.

The Buckingham Canal is a salt water navigation canal dug in the nineteenth century along the eastern coast, linking the lagoons and backwaters between Vijayawada in Andhra Pradesh and Chennai in Tamil Nadu, and it was used to carry goods and to relieve famine by moving grain.

The Grand Anicut, known in Tamil as Kallanai, was thrown across the Cauvery by the Chola king Karikala in about the second century to spread the river's water over the delta, and it still serves the canals of the Cauvery delta in Tamil Nadu.

The Upper Ganga Canal was opened in 1854 and is taken from the Ganga at Haridwar, from where it runs down the Ganga–Yamuna Doab and irrigates the districts of western Uttar Pradesh; the engineer associated with its construction is Proby Cautley.

The Harike barrage stands in Punjab at the point where the Beas joins the Sutlej, and the Indira Gandhi Canal begins there as the Rajasthan Feeder before continuing as the main canal into Rajasthan.

Begun in 1958 as the Rajasthan Canal and renamed in 1984, it is the longest canal in India; its feeder and main canal together run for about six hundred and fifty kilometres and carry water from the Punjab rivers into the Thar desert of western Rajasthan.

The skin is the largest organ of the human body by both surface area and weight, and it is the organ of touch; it is made of an outer epidermis and an inner dermis that carries blood vessels, nerve endings, hair follicles, sweat glands and sebaceous glands.

Rhodopsin, the pigment of the rod cells that makes vision in dim light possible, is formed from a derivative of vitamin A, so when the vitamin is lacking the rods cannot work properly and the person is unable to see in faint light, a condition called night blindness or nyctalopia…

The Eustachian tube, also called the auditory tube, runs from the cavity of the middle ear to the nasopharynx, the upper part of the throat behind the nose, and its function is to keep the air pressure on the inner side of the eardrum equal to the pressure outside.

The blind spot, also called the optic disc, is the small area of the retina from which the fibres of the optic nerve pass out of the eyeball; it has neither rods nor cones, so an image falling on it is not registered and we do not notice the gap…

In myopia the eyeball is too long or the lens too strongly curved, so light from a distant object is brought to a focus in front of the retina and the distant object appears blurred.

Rhodopsin, also called visual purple, is the pigment of the rod cells; it is extremely sensitive to light, which is why rods allow us to see in dim light, though only in shades of black and white.

The retina is the innermost coat of the eyeball and it carries the photoreceptor cells, the rods and the cones, which convert light into nerve impulses that the optic nerve carries to the brain; the image formed on the retina is real and inverted, and the brain interprets it as…

The three semicircular canals of the inner ear are set at right angles to one another and are filled with fluid; movement of the head moves the fluid, which stimulates the receptors and tells the brain about the position and motion of the head, so that balance or equilibrium is…

The stapes, also called the stirrup because of its shape, lies in the middle ear and is the smallest bone in the human body; it passes the vibration received from the eardrum on to the oval window of the inner ear.

Gustatory receptors are the receptors of taste, and they lie in the taste buds of the tongue, which sit mostly on small projections called papillae; they are stimulated by chemicals dissolved in saliva and send impulses to the brain.

The iris is the coloured ring in front of the lens, formed by the front part of the choroid, and the muscles in it widen or narrow the pupil so that the right amount of light reaches the retina; in dim light the pupil opens wide and in bright light…

Carborundum, or silicon carbide (SiC), is one of the hardest substances known, so it can grind, cut and polish other materials, which is what an abrasive must do.

Too little fluoride in drinking water leaves tooth enamel weak, so teeth decay more easily and develop cavities, called dental caries.

The inner planets are the four that orbit the Sun inside the asteroid belt: Mercury, Venus, Earth and Mars. The asteroid belt between Mars and Jupiter divides the solar system into two groups.