Railway GK Questions 2026

A Lagrange point is a place where the gravitational pulls of the two bodies and the orbital motion balance, so a spacecraft can stay there with very little fuel, and from L1 the sun can be watched continuously without eclipse or occultation.

Astrosat was launched on 28 September 2015 by a PSLV and carries instruments that observe the same cosmic source in the ultraviolet, the visible and the X-ray bands at the same time, which is what multi-wavelength means and what makes the mission unusual among space telescopes of its size.

Launched in 2002 as METSAT, it was the first Indian satellite built only for weather work, and it was renamed Kalpana-1 in memory of Kalpana Chawla, the India-born astronaut who died in the Columbia accident of 2003.

The system was designed as a constellation of seven satellites, three of them in geostationary orbit and four in geosynchronous orbits inclined to the equatorial plane, a small number being enough because the service area is regional and not global.

The name was given in 2016 to the Indian Regional Navigation Satellite System, IRNSS, when the seventh satellite of the constellation was placed in orbit, and the word navik also carries the sense of a sailor or navigator, which is why it was chosen.

It was launched on 19 April 1975 by a Soviet launch vehicle, since India had no vehicle of its own at the time, and it carried experiments in X-ray astronomy, solar physics and the ionosphere.

It has three solid stages and a small liquid velocity trimming module, carries up to about 500 kg to a 500 km low earth orbit, and is designed to be assembled and launched by a small team within days so that a customer with one satellite need not wait for…

That flight carried the GSAT-14 communication satellite and was the first success of the indigenous cryogenic upper stage, which put India among the small group of countries able to build such an engine.

Its companion, the Liquid Propulsion Systems Centre, develops the liquid and cryogenic engines that those vehicles fly with.

PSLV-C37 carried the Cartosat-2 series satellite as its main passenger along with two Indian nano-satellites and 101 small foreign satellites, releasing all of them one after another from its restartable liquid fourth stage.

It is India's only orbital launch site, on the east coast, so vehicles can fly out eastwards over the Bay of Bengal and take the free gain from the earth's rotation while the spent stages fall harmlessly into the sea.

Chandrayaan-1 went up on PSLV-C11 in October 2008 and the Mars Orbiter Mission on PSLV-C25 in November 2013, both in the extended PSLV-XL configuration with six long strap-on motors.

The GSLV has three stages: a solid core first stage with four liquid strap-on motors, a liquid second stage using a Vikas engine, and a cryogenic upper stage that burns liquid hydrogen with liquid oxygen.

The PSLV is unusual in alternating propellants between its stages: the first and third stages burn solid propellant and the second and fourth burn liquid propellant.

On 18 July 1980 the four-stage, all-solid SLV-3 placed the small Rohini RS-1 satellite in a low earth orbit from Sriharikota, and India became the sixth nation able to launch its own satellite.

Chandrayaan-3 weighed close to 3,900 kg at lift-off, far beyond the reach of any lighter Indian rocket, so it flew on LVM3, the vehicle earlier named GSLV Mk III.

The Jammu and Kashmir Reorganisation Act, 2019 took effect on 31 October 2019 and replaced the former state with two Union Territories.

All three came into being within a fortnight in November 2000: Chhattisgarh from Madhya Pradesh on 1 November, Uttarakhand, then named Uttaranchal, from Uttar Pradesh on 9 November, and Jharkhand from Bihar on 15 November.

Sikkim became the twenty-second state of the Indian Union on 16 May 1975 through the Constitution (Thirty-sixth Amendment) Act, 1975, which placed it in the First Schedule as a state and added Article 371F for special provisions relating to it.

It was formed on 2 June 2014 under the Andhra Pradesh Reorganisation Act, 2014, out of the north-western districts of Andhra Pradesh, and Hyderabad was made the common capital of both states for a transitional period.