IAS Prelims GS Questions and Answers - May 05, 2016

ANSWER: Dosimeter

Explanation:

• A radiation dosimeter is a device that measures exposure to ionizing radiation. It has two main uses: for human radiation protection and for measurement of dose in both medical and industrial processes.
• Ionising radiation damage to the human body is cumulative, and is related to the total dose received, for which the SI unit is the sievert.
• Workers exposed to radiation, such as radiographers, nuclear power plant workers, doctors using radiotherapy, those in laboratories using radionuclides, and HAZMAT teams are required to wear dosimeters so a record of occupational exposure can be made. Such devices are known as "legal dosimeters" if they have been approved for use in recording personnel dose for regulatory purposes.
• Dosimeters can be worn to obtain a whole body dose and there are also specialist types that can be worn on the fingers or clipped to headgear, to measure the localised body irradiation for specific activities.

ANSWER: Cobalt - 60

Explanation:

• Radiation Sterilisation is a cold process that uses gamma radiation for sterilisation of Healthcare Products.
• Controlled gamma energy which is released by radioisotope such as Cobalt-60 is used for sterilisation.
• Cobalt-60 is most preferred radioisotope as it is readily available from single nuclear reaction in reactor and also cost effective.
• Gamma radiation is characterised by deep penetration and kills microorganism by destroying DNA structure. The process is suitable for Industrial scale sterilisation.

ANSWER: Only 1

Explanation:

• Controlled gamma energy which is released by radioisotope such as Cobalt-60 is used for sterilisation.
• High energy Electron Beam (EB) and X-ray machines are also used nowadays for this purpose. The major difference in gamma radiation and EB lies in their penetration powers, where gamma radiations can penetrate deep inside the products the electron beams do not have as good penetration power.
• Though X-ray have comparable penetration power to gamma radiation at suitable energy range but they are not yet very popular.
• Gamma radiation is characterised by deep penetration and kills microorganism by destroying DNA structure. The process is suitable for Industrial scale sterilisation.

ANSWER: 2

Explanation:

• The Coal is the main source of power generation in the country.
• There are broadly two categories of coal based Thermal power plants: (i) Pit Head based plants, which are situated near coal Mines and (ii) Load centre based plants situated near load centres.
• Power Plants are having different efficiency levels for conversion of coal to electricity depending upon their technology, unit capacity etc.
• At present, there are situations where efficient power plants have shortage of coal while some other Power Stations have adequate coal available with them because of less capacity utilization.
• The Union Cabinet has given its approval for allowing flexibility in utilisation of domestic coal for reducing the cost of power generation.
• The objective of the proposal is to allow flexibility in optimal use of domestic coal in efficient Generating Stations resulting in reduction in the cost of electricity generation and reduce the power purchase cost of State Distribution companies. Such flexibility will be able to leverage coal to electricity conversion, efficiency of equipment as well as transportation cost optimization.
• This would create new thrust in promoting efficiency, optimum utilization of natural resources as well as overall economic benefit in the power sector in the country.
• This will result in coal transportation cost reduction as well as savings in energy used for transportation and may also result in removal of congestion of Railways network.
• This will also be a more environment friendly arrangement as less coal will be used to produce more power and also the distance for transportation of coal would be optimized.

ANSWER: 1, 2

Explanation:

• A beta particle, sometimes called beta ray, denoted by the lower-case Greek letter beta (β), is a high-energy, high-speed electron or positron emitted in the radioactive decay of an atomic nucleus, such as a potassium-40 nucleus, in the process of beta decay.
• Two forms of beta decay, β- and β+, respectively produce electrons and positrons.
• Beta particles are a type of ionizing radiation.

ANSWER: Helium Nucleus

Explanation:

• Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and thereby transforms or 'decays' into an atom with a mass number that is reduced by four and an atomic number that is reduced by two.
• An alpha particle is identical to the nucleus of a helium-4 atom, which consists of two protons and two neutrons.
• Gamma rays consist of Photons.

ANSWER: 1, 2, 4

Explanation:

• Ionizing (or ionising in British English) radiation is radiation that carries enough energy to free electrons from atoms or molecules, thereby ionizing them.
• Gamma rays, X-rays, alpha particles, beta particles, Positrons and other types of antimatter, Photon radiation, charged nuclei and the higher ultraviolet part of the electromagnetic spectrum are ionizing.
• Whereas the lower ultraviolet part of the electromagnetic spectrum, and also the lower part of the spectrum below UV, including visible light (including nearly all types of laser light), infrared, microwaves, and radio waves are all considered non-ionizing radiation.
• The boundary between ionizing and non-ionizing electromagnetic radiation that occurs in the ultraviolet is not sharply defined, since different molecules and atoms ionize at different energies. Conventional definition places the boundary at a photon energy between 10 eV and 33 eV in the ultraviolet

ANSWER: Exchange loan and/or interest amounts in one currency for equivalent amount in another currency

Explanation:

• A currency swap (or a cross currency swap) is a foreign exchange derivative between two institutions to exchange the principal and/or interest payments of a loan in one currency for equivalent amounts, in net present value terms, in another currency.
• Currency swaps are motivated by comparative advantage.

ANSWER: Team detecting gravitational waves

Explanation:

• The scientists and engineers of the LIGO Scientific Collaboration, who detected gravitational waves and reported their discovery in February, have been awarded a $3 million Special Breakthrough Prize in Fundamental Physics.
• The team also includes Indian scientists and researchers.
• The three founders of the Laser Interferometer Gravitational-Wave Observatory (LIGO) are Rainer Weiss, emeritus professor of physics at MIT; Kip Thorne, Caltech’s Richard P. Feynman Professor of Theoretical Physics, emeritus; and Ronald Drever, emeritus professor of physics at Caltech.