NDA GK Questions 2026

At that height a satellite's orbital period equals the period of the earth's rotation, so it stays above the same point on the equator and appears fixed in the sky, which is what communication and weather satellites need.

An active sensor generates its own energy, sends it to the target and measures what returns; RADAR does this with microwaves and LiDAR with a laser pulse, which is why such sensors can image at night and, in the case of microwaves, through cloud, haze and smoke.

It was the first satellite of the Indian Remote Sensing series and marked the beginning of operational earth observation for agriculture, forestry, water resources and land use in India.

Since the contour interval is constant on a sheet, the horizontal distance between two contours measures how far one must walk to rise by that fixed height; a short distance therefore means a rapid rise, that is a steep slope.

An isohyet joins points receiving the same amount of precipitation over a stated period, and rainfall maps of India are drawn with isohyets to mark the wet and dry belts.

Mercator's is a cylindrical projection on which both parallels and meridians are straight lines crossing at right angles, and it is orthomorphic or conformal, meaning that shapes are true locally and a rhumb line of constant bearing plots as a straight line.

The contour interval chosen for a sheet depends chiefly on its scale and on the relief of the ground: a large-scale map can carry closely spaced contours without the lines running into each other, so a small interval is both possible and desirable.

The representative fraction is a pure ratio without units, so one unit of length on the map stands for fifty thousand of the same units on the ground; it can be read in centimetres, inches or any other unit, which is why it is understood everywhere.

The correct answer is A, Aspergillus niger, a fungus grown on a sugar medium to make most of the world's citric acid, which is used in soft drinks, food and medicines.

The short, sharp heating kills the disease-causing and most spoilage microbes while leaving the taste and most of the food value of the milk unchanged, which is exactly what boiling does not do.

A virus has heredity and mutates like a living thing, yet it has no cell, no metabolism and no means of reproduction of its own; outside a host it is an inert particle that can even be crystallised, as W. M. Stanley showed with the tobacco mosaic virus in 1935…

It spreads through droplets in the air, chiefly attacks the lungs, and is treated with a long and uninterrupted course of several antibiotics.

The yeast Saccharomyces cerevisiae ferments the sugars of the dough into ethanol and carbon dioxide, and the gas, trapped in the gluten, makes the dough rise and leaves the bread spongy; the alcohol evaporates during baking.

Fungi are eukaryotes with a true nucleus, and their wall is built of chitin, the same tough polysaccharide that forms the exoskeleton of insects and crustaceans.

It lives in a symbiotic relationship inside the nodules on the roots of gram, pea, groundnut and other legumes, converting atmospheric nitrogen into compounds the plant can absorb while drawing its food from the plant.

The correct answer is B, measles, a viral disease spread by droplets, which is why it is prevented by vaccination and not treated with antibiotics.

It is the target of penicillin, which blocks its formation, and the amount of it in the wall is what makes a bacterium stain Gram-positive or Gram-negative.

Malaria is caused by the protozoan parasite Plasmodium, of which several species infect human beings, and it is transmitted by the bite of an infected female Anopheles mosquito, the male feeding on plant juices.

He noticed that a mould of the genus Penicillium growing by accident on a culture plate had stopped the growth of Staphylococcus around it, and Howard Florey and Ernst Chain later turned that observation into a usable drug, the three sharing the Nobel Prize.

This bacterium ferments the lactose of milk into lactic acid, and the acid makes the milk protein coagulate, which is why a spoonful of old curd added to warm milk sets the whole vessel.