RRB JE GK Questions 2026

Doping replaces a few host atoms with impurity atoms, and each impurity atom brings its own nucleus along with its electrons, so the total positive and negative charge in the crystal stays balanced.

John Bardeen, Walter Brattain and William Shockley built the first working transistor at Bell Laboratories in 1947 and shared the Nobel Prize in Physics in 1956 for the discovery of the transistor effect.

A full-wave rectifier conducts during both halves of the input cycle, since one pair of diodes handles the positive half and the other pair the negative half.

They are called universal gates because either one of them, used repeatedly, can build every other logic gate, including NOT, AND, OR, XOR and XNOR.

The base of a transistor is made very thin and only lightly doped so that most of the carriers injected by the emitter pass straight through it to the collector instead of recombining in it.

A Zener diode is heavily doped so that breakdown occurs at a low and sharply defined reverse voltage. Beyond that point the voltage across it stays almost constant even when the current through it changes a great deal, which is precisely the property a voltage regulator needs.

A p-n junction conducts freely in forward bias, where the potential barrier is reduced, and blocks current in reverse bias, where only a tiny leakage current flows.

Silicon is the most widely used semiconductor and its forbidden energy gap, the separation between the top of the valence band and the bottom of the conduction band, is about 1.1 electron volts at room temperature.

A p-type semiconductor is made by adding a trivalent impurity such as boron, aluminium, gallium or indium.

An n-type semiconductor is made by doping with a pentavalent element, that is one with five valence electrons, such as phosphorus, arsenic, antimony or bismuth.

A semiconductor has a small forbidden energy gap, so heating supplies thermal energy that pushes more electrons from the valence band into the conduction band, creating more electron-hole pairs.

He addressed the Chintan Shivir and pressed for wider use of digital technologies, GPS-based monitoring and artificial intelligence in field verification, monitoring and timely decision-making, while also seeking faster preparation of Detailed Project Reports, better construction quality and stronger accountability.

The current phase of the Pradhan Mantri Gram Sadak Yojana is designed to provide connectivity to 25,000 eligible unconnected habitations, and to do so it targets roughly 62,500 km of all-weather roads with an outlay of Rs 70,125 crore.

Under PMGSY-IV, with this outlay, about 62,500 km of all-weather roads are targeted so that 25,000 eligible unconnected habitations receive connectivity.

The first two are institutions of the Department of Science and Technology, and the team was led by Dr. Pradip Pachfule, Prof. Ramendra Sundar Dey and Prof. Ranjit Thapa respectively, with the findings published in the journal Science Advances.

Tests showed that even after that long a spell of continuous running, the material kept its performance and did not suffer the degradation or contamination that commonly affects catalysts built around metals.

Many clean-energy technologies, and hydrogen fuel cells in particular, depend on platinum to speed up the oxygen reduction reaction, and because it is one of the rarest and most expensive metals available, its cost and limited supply stand in the way of large-scale use.

More than four years after the strategy was issued, the government reports that 56 additive manufacturing start-ups have been supported, strengthening the country's innovation and entrepreneurship base.

ESTIC is India's Emerging Science, Technology and Innovation Conclave, and its second edition is organised by CSIR on the theme 'Creative Minds, Catalyzing Science, Empowering Technologies'.

The national strategy sets a time-bound goal of capturing a twentieth of the world additive manufacturing market and of adding close to one billion US dollars to India's gross domestic product.