Railway GK Questions 2026

India proposed the day at the United Nations General Assembly, which adopted the resolution in December 2014, and the first observance was held in 2015; the date was chosen because 21 June is the summer solstice, the longest day of the year in the northern hemisphere.

World AIDS Day has been observed on the first of December since 1988 and was the first global health day of its kind, its symbol being the red ribbon; the theme changes every year and the day is used to press for testing, treatment and an end to stigma.

The day marks the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer on 16 September 1987, an agreement to phase out chlorofluorocarbons and other ozone destroying chemicals, and it is often called the most successful environmental treaty.

The Convention on Wetlands was signed on 2 February 1971 in the Iranian city of Ramsar on the shore of the Caspian Sea, and the wetlands listed under it are still called Ramsar sites; the day has been observed on this date since 1997.

The constitution of the World Health Organization took effect on 7 April 1948, and the anniversary of that day has been kept as World Health Day since 1950, with a theme chosen by the organisation; its headquarters are at Geneva in Switzerland.

World Environment Day marks the opening of the United Nations Conference on the Human Environment held at Stockholm in 1972, and it has been observed since 1974 under the lead of the United Nations Environment Programme, with a fresh theme and a host country each year.

The internet joins networks in every country through undersea cables, optical fibre on land and satellite links, all of them following the common TCP/IP rules, and no single organisation owns it, so it is rightly called the largest wide area network and a network of networks.

The Transmission Control Protocol first sets up a connection through a three-way handshake, then numbers every segment, waits for an acknowledgement for each and sends it again if none arrives, and finally hands the data to the application in the original order.

Full duplex means both ends can send and receive at the very same moment, and on a telephone call each speaker can talk while still hearing the other, so traffic flows in both directions together.

The registered jack numbered 45 is the eight-pin plastic plug crimped on the end of an unshielded twisted pair Ethernet cable, and it is what clicks into the network port of a computer, a switch or a router.

In a ring the machines form a closed loop and a small control frame called a token keeps circulating around it; only the computer holding the token may put data on the ring, and when it finishes it releases the token to the next machine.

The Media Access Control address is the permanent physical address written into the network interface card by its maker, and it is 48 bits long, shown to users as twelve hexadecimal digits in six pairs such as 00:1A:2B:3C:4D:5E. The first half identifies the manufacturer and the second half the particular…

A router joins two or more different networks and decides, for every packet, which outgoing line will carry it towards its destination.

In a full mesh every node is joined directly to every other node, so the number of links equals the number of pairs that can be formed from the nodes, given by the formula n(n-1)/2.

In a star network every computer has its own cable running to a central hub or switch, so the shape resembles the spokes of a wheel.

GPRS was added to the 2G cellular system so that the same radio channel could carry data in packets instead of holding a circuit open the way a voice call does.

A modulator changes the form of a signal: it loads the digital bits produced by a computer onto an analog carrier wave so that they can travel over a telephone line, a cable or a radio link.

The attack surface of a system is the total collection of every point at which an unauthorised person could try to enter it or pull data out of it: open ports, running services, user accounts, login pages, removable drives and even the employees who can be tricked.

Amartya Sen published this book in 1981 and showed, using the Bengal famine among other cases, that famines occur not merely because food is short in a country but because groups of people lose the ability to command food, which he called a failure of entitlement; the work was central…

The Swedish economist Gunnar Myrdal published this long three-volume study of South and South East Asia in 1968, examining why the region stayed poor and pointing to institutions, land relations, administration and what he called the soft state; the title deliberately echoes Adam Smith's Wealth of Nations.