RRB ALP GK Questions 2026

Phosphorus, sulphur, chlorine and argon all sit in the third period of the periodic table, so their electrons fill the same three shells.

Group 15, the nitrogen family, holds nitrogen, phosphorus, arsenic, antimony and bismuth. Only nitrogen and phosphorus are non-metals; arsenic and antimony are metalloids and bismuth is a metal, so the group has exactly two non-metallic elements.

Heating a semiconductor gives more electrons enough energy to cross the forbidden gap into the conduction band, and each one that crosses leaves a hole behind, so the number of charge carriers rises sharply and the resistance falls; a semiconductor therefore has a negative temperature coefficient of resistance.

The Semi-Conductor Laboratory at Mohali in Punjab works under the Ministry of Electronics and Information Technology and is India's own fabrication unit, producing chips at an older process node for strategic users such as the Indian Space Research Organisation and the Defence Research and Development Organisation rather than for the…

Chip making has three broad stages: design, which is done by fabless companies and design houses; fabrication, in which circuits are built on a silicon wafer in a fab; and the back end, in which the wafer is cut into individual chips that are then assembled, tested, marked and packaged…

The India Semiconductor Mission was set up to carry out the Semicon India programme, which the Union Cabinet approved in December 2021 with an outlay of 76,000 crore rupees, and it works as a specialised division under this ministry, handling the schemes for semiconductor fabs, display fabs, compound semiconductor and…

Gordon Moore, a co-founder of Intel, observed in 1965 that the number of components that could be packed economically into an integrated circuit was doubling at a steady rate, and the observation, later quoted as a doubling roughly every two years, became the planning rule of the whole industry.

Beta is the current gain of a bipolar junction transistor in the common emitter configuration: a very small change in the base current produces a much larger change in the collector current, and the ratio of the two is beta, which commonly lies between about twenty and several hundred.

In a bipolar junction transistor the emitter injects carriers, the thin lightly doped base lets most of them through, and the collector gathers them, so the emitter current divides into a large collector current and a small base current; alpha is defined as the collector current divided by the emitter…

John Bardeen, Walter Brattain and William Shockley built the first working transistor at Bell Laboratories in the United States in 1947, and the three shared the Nobel Prize in Physics in 1956 for the discovery of the transistor effect; the device replaced the bulky vacuum tube and made all later…

A trivalent dopant such as boron, aluminium, gallium or indium forms only three covalent bonds with the surrounding silicon atoms, leaving one bond incomplete; that vacancy behaves as a mobile positive carrier called a hole, and holes therefore become the majority carriers while thermally generated electrons remain the minority carriers.

Silicon has four valence electrons, so adding a pentavalent atom such as phosphorus, arsenic, antimony or bismuth leaves one electron over after four bonds are formed; that spare electron is loosely held and becomes a free carrier, making electrons the majority carriers and the crystal n-type.

In an intrinsic, that is a chemically pure, semiconductor every free electron is produced by breaking a covalent bond, and breaking a bond leaves behind exactly one hole, so electrons and holes are created strictly in pairs and their concentrations must be equal.

The energy gap between the valence band and the conduction band decides whether a solid conducts: in silicon the gap is roughly 1.1 electron volts, small enough for heat or light to lift some electrons across it, which is what makes silicon a semiconductor.

Ampere-turns per metre, written AT/m, is the unit of magnetic field strength, because H is the magnetomotive force set up per unit length of the magnetic path.

Concentration tells how much solute is present in a given amount of solution, and the three standard percentage forms are mass by mass, mass by volume and volume by volume; volume by mass is not one of them.

The Tyndall effect is the scattering of a beam of light by particles suspended in a medium, and it needs particles large enough to scatter that light.

Sulfur dioxide is made of one sulfur atom and two oxygen atoms, so its molecular mass is the sum of their atomic masses: 32 plus 2 multiplied by 16, that is 32 plus 32, which gives 64 u. Molecular mass is expressed in unified atomic mass units, written u, and…

Calcium chloride is an ionic compound, so it has a formula unit mass rather than a molecular mass, and the value is found by adding the atomic masses of all the atoms in the formula.

Bacteria in the mouth break down leftover food particles and produce acid, not base, so statement d is the incorrect one.