science & tech MCQ section 5 MCQ Questions & Answers Detailed Explanation

Answer: (b)

Callisto, Europa and Ganymede are the satellites of Jupiter. Deimos is a natural satellite of the planet Mars.

Answer: (c)

Space Craft Rosetta, covered a distance of about 6.5 billion KM. The goal of this arduous journey has been to rendezvous with Comet 67P.

Answer: (d)

NASA’s Cassini spacecraft has identified 101 geysers on Saturn’s moon Enceladus suggesting possibility of liquid water.

Answer: (c)

Agni II is an Intermediate Range Ballistic Missile of India. It is a missile with two solid fuel stages and a Post Boost Vehicle (PBV) integrated into the missile's Re-entry Vehicle (RV). It is both road and rail mobile. In the Agni series of ballistic missiles, Agni II, Agni III and Agni IV are IRBMs.

Answer: (d)

Lukosin is a herbal drug developed by Defense Research Development Organisation(DRDO) for treatment of Lucoderma( White patches on skin).

Answer: (d)

The total annual external dose from sources in soil and cosmic rays in Mumbai, Kolkata, Chennai, Delhi and Bengaluru is 0.484, 0.81, 0.79, 0.70 and 0.825 milligray respectively. Gray is a unit for absorbed dose; when the radiation energy imparted to a kg of material is one joule, it is called a gray.

Since gray is very large, milligrays (one-thousandth of a gray), and microgray (one-millionth of a gray), are commonly used. Cosmic rays come from outer space. Their intensity at a place depends on the altitude. Cosmic rays alone contribute 0.28 milligrays at the first three cities as they are at sea level; the column of air helps to reduce their intensity.

At high altitudes, the protection from the column of air is less. The cosmic ray contributions are higher at 0.31 milligray and 0.44 milligray respectively at Delhi and Bengaluru as these cities are at altitudes of 216 metres and 921 metres. Air passengers receive 5 micrograys per hour from cosmic rays. Parts of Kerala and Tamil Nadu are high background radiation areas (HBRA) because of the presence of large quantities of monazite in the soil.

Thorium content in monazite ranges from 8-10.5 per cent. Researchers found that the radiation levels in 12 Panchayats in Karunagappally varied between 0.32 to 76 milligrays per year; the levels in 90 per cent of over 71,000 houses were more than one milligray per year.