RRB JE GK Questions 2026

A computer works with digital signals, a series of ones and zeros, while an ordinary telephone line was built to carry an analog voice signal.

The RJ-45 is the eight-position modular plug crimped on to the end of an unshielded twisted pair cable of category 5e or 6 and pushed into the network port of a computer, switch or router.

A walkie-talkie allows both parties to speak and both to listen, so communication is two-way, but the set has a single push-to-talk switch and one person must release it before the other can be heard.

Electromagnetic interference acts on moving charge, so any medium that carries a signal as an electric current can pick up noise from motors, fluorescent lamps, lightning and nearby cables.

The fibre has a core of higher refractive index surrounded by a cladding of lower refractive index. Light that enters the core and meets the boundary at an angle greater than the critical angle is reflected entirely back into the core, with none of it refracted away into the cladding.

In frequency division multiplexing each channel is given its own slice of the frequency band, and a small unused strip called a guard band is left between two neighbouring channels so that one does not spill into the next.

At the transmitting end of a fibre link the electrical signal must be turned into light, and the two devices that do it are the light-emitting diode and the laser diode.

An optical fibre carries information as pulses of light, not as an electric current, so its core and cladding must be transparent and not conducting.

The transmitter of an optical fibre link must be small enough to couple light into a core a few micrometres across, must switch on and off millions or billions of times a second, and must emit in a narrow band of wavelengths; a light-emitting diode meets these conditions, and for…

At the receiving end of an optical fibre link the light pulses must be turned back into an electrical signal, and that is the work of a photodiode, a reverse-biased junction in which incident photons generate charge carriers and so a current proportional to the light falling on it; PIN…

A fibre-to-the-home connection runs from the operator's equipment to the subscriber's premises over a distance of kilometres, and for such runs single-mode fibre is used: its core is only a few micrometres wide, so light travels along one path, there is no spreading of the pulse from different paths arriving…

In an optical fibre the glass core has a higher refractive index than the cladding around it, so light that meets the core-cladding boundary at an angle greater than the critical angle is reflected entirely back into the core instead of passing out, and it travels along the fibre in…

The International Telecommunication Union has adopted the framework recommendation for IMT-2030, which describes what 6G should achieve: terahertz and other very high frequency bands, latency below a millisecond, artificial intelligence built into the network, communication combined with sensing, satellite-extended coverage and better energy efficiency.

TRAI was set up under the Telecom Regulatory Authority of India Act, 1997, to regulate telecom services, fix tariffs and protect the interests of consumers once private operators entered the field.

The first mobile telephone call in India was made on 31 July 1995 between Kolkata and New Delhi, a year after the National Telecom Policy of 1994 opened mobile services to private operators.

The three categories actually defined are given in the other options.

Under IMT-2020 the peak downlink data rate for 5G is set at 20 gigabits a second, with 10 gigabits a second in the uplink; these are laboratory peaks under ideal conditions, not the speed a subscriber sees, and the separate target for the user experienced rate is 100 megabits a…

LTE is the radio technology through which 4G was delivered; the name was chosen because it was presented as the long-term evolution of the earlier 3G standards rather than a break with them.

The International Telecommunication Union names each generation of mobile telephony by a standard family, and 5G is IMT-2020, whose requirements include a peak downlink rate of 20 Gbps, a user experienced rate of 100 Mbps, one millisecond of air interface latency and a million connected devices in a square kilometre.

Commercial 5G services began in India on 1 October 2022, when they were launched at the India Mobile Congress in New Delhi, following the spectrum auction held earlier that year in the 600 MHz, 700 MHz, 3300 MHz and 26 GHz bands among others.