As per the standards set by the Department of Telecom, Government of India, for all the new designs of mobile handsets, the permissible Specific Absorption Rate (SAR) limit is _______ averaged over 1 gram of human tissue with effect from 1st September 2012.

The correct answer is C, Chandipur, Odisha. Prithvi II is test-fired from the Integrated Test Range at Chandipur on the Odisha coast, the DRDO range used for missile and rocket trials. Prithvi II is a surface-to-surface short-range ballistic missile of the Indian Air Force, developed under the Integrated Guided Missile Development Programme that Dr A.P.J. Abdul Kalam led. It runs on liquid propellant, has a range of about 350 km and can carry a warhead of 500 to 1,000 kg. Option A is wrong because Rutland Island in the Andamans has no missile test range. Option B is wrong because Sriharikota in Andhra Pradesh is ISRO's launch centre for satellites, not a missile range. Option D is wrong because Machilipatnam is a coastal town with no such facility. Exam tip: the IGMDP missiles are Prithvi, Agni, Trishul, Akash and Nag; missiles are tested at Chandipur, while satellites go up from Sriharikota.

The correct answer is B, the first Lagrange point, L1, of the sun and earth system, about 1.5 million kilometres from the earth towards the sun. 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. Aditya-L1 was launched on 2 September 2023 by a PSLV.

Option A, L2, lies on the far side of the earth from the sun and is used by telescopes that look away from the sun. Option C is wrong because the spacecraft orbits a point in the sun-earth system, not the sun itself. Option D would put it in earth orbit, where the earth would block the view for part of every day, which is precisely what the mission had to avoid. Remember the pair: L1 for solar watching, 1.5 million km.

The correct answer is B, seven. 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. IRNSS-1G, launched in April 2016, completed the seven.

Option A, four, is the number of inclined satellites alone and is the trap for a candidate who remembers the split but not the total. Option D, twenty-four, is roughly the size of a global constellation such as GPS, which needs satellites spread over the whole earth. Option C, nine, matches no system. Remember the split as three plus four, and remember that the second-generation NVS satellites are replacing the first-generation ones as they age.

The correct answer is B, a dedicated multi-wavelength space observatory. 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.

Option A describes the RISAT series, which images the ground through cloud and at night using radar. Option C describes the IRNSS and NVS satellites of the NavIC constellation. Option D describes EDUSAT of 2004, the first Indian satellite meant only for education and classroom broadcasting. Two other science missions belong in the same list of firsts: Aditya-L1 of 2023, the first solar observatory, and XPoSat of 2024, which studies the polarisation of cosmic X-rays.

The correct answer is B, Kalpana-1. 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. Its instruments watched cloud cover, water vapour and sea surface temperature for cyclone warning.

Option A, INSAT-1B of 1983, carried meteorological instruments but was primarily a communication satellite, which is the distinction the word exclusively tests. Option C, Bhaskara-2, belonged to the early experimental earth observation series of 1979 and 1981. Option D, Oceansat-1 of 1999, studied the sea, its colour and winds over it, so it is an ocean rather than a weather satellite. The later dedicated weather satellites in this line are the INSAT-3D series.