UPSC GK Questions 2026

An implicit cost is the imputed value of a factor supplied by the entrepreneur himself, for which no payment leaves the firm; the rent he could have earned by letting out his own premises, the interest on his own capital and the salary he could have drawn elsewhere are the…

Marginal cost is the addition to total cost from producing one more unit, so for a one unit change it is simply the difference between successive values of total cost.

At that output the firm makes neither profit nor loss in the economic sense and earns only normal profit, since normal profit is already counted in cost as the reward of enterprise.

Both conditions are needed. If marginal revenue exceeds marginal cost the firm gains by producing more, and if marginal cost exceeds marginal revenue it gains by producing less, so profit can be highest only where they are equal; and the equality must occur on the rising part of the marginal…

A firm in perfect competition is a price taker because its output is a negligible part of the market, so it can sell any quantity at the ruling price.

This is the defining condition of the short run, where plant and machinery cannot be changed, so only the proportion between the variable factor and the fixed factor alters.

The reason is arithmetic rather than economic: so long as marginal cost is below average cost, each extra unit pulls the average down, and once marginal cost rises above average cost the average must rise, so the two can only be equal where the average is at its lowest.

Average fixed cost is total fixed cost divided by output; the numerator is unchanged, so a larger output spreads the same fixed cost over more units.

Fixed cost is the payment for factors that cannot be varied in the short run, such as the rent of the factory building, insurance and the salary of permanent staff, and it has to be met even when output is zero, which is why it is also called supplementary or…

Kolleru is a large shallow freshwater lake lying between the deltas of the Krishna and the Godavari, fed by the Budameru and Tammileru streams; it is a natural flood balancing reservoir for the two deltas and an important wintering ground for pelicans and other water birds.

It lies in the Kashmir valley in Jammu and Kashmir, is fed by the Jhelum and occupies a tectonic depression, which makes it the largest freshwater lake of India.

The Iguazu river falls in a horseshoe of hundreds of separate cascades just above its junction with the Parana, and the two countries have national parks on either side of the fall.

It lies in the Jordan rift valley between Israel and Jordan, more than four hundred metres below sea level, and its extreme salinity, caused by heavy evaporation with no outlet, lets a swimmer float easily.

The White Nile leaves Lake Victoria at Jinja in Uganda and flows north through Lake Kyoga and Lake Albert to meet the Blue Nile at Khartoum, where the Nile proper begins.

Lake Titicaca lies on the Altiplano of the Andes at about 3,810 metres above sea level and carries regular boat traffic, which is why it is called the highest navigable lake in the world.

Of the five lakes remembered by the word HOMES, Huron, Ontario, Michigan, Erie and Superior, only Michigan lies wholly in the United States; the international boundary with Canada runs through the other four.

The Niagara river carries the water of Lake Erie to Lake Ontario, and on the way it crosses the Niagara escarpment, a band of hard dolomite, which produces the Horseshoe, American and Bridal Veil falls on the border of Canada and the United States.

The falls lie on the border of Zambia and Zimbabwe, where the Zambezi drops into a basalt gorge; the local name Mosi-oa-Tunya means the smoke that thunders, and the missionary explorer David Livingstone named them after Queen Victoria in 1855.

Angel Falls, called Salto Angel in Spanish, drops about 979 metres from the Auyan Tepui, one of the flat topped table mountains of the Guiana highlands, and is fed by the Churun river, a tributary of the Caroni.

It is a landlocked salt lake bordered by Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan, the remnant of the ancient Tethys sea, and is called a sea only by custom.