www.facebook.com/groups/abwf4india Facebook Group: Indian Administrative Service ( Raz Kr) RazKr [Live] - https://telegram.me/RazKrLive Notes 16 July 2015 20:07 Dream 2047, Science Reporter, Black box in aeroplanes Science Page 1 www.facebook.com/groups/abwf4india Facebook Group: Indian Administrative Service ( Raz Kr) RazKr [Live] - https://telegram.me/RazKrLive General science 13 September 2013 21:23 General Science NIOS, Std'10 Science TN, Imp points • According to Article 51a(h) of our Constitution, it is the fundamental duty of every citizen “to develop the scientific temper, humanism & the spirit of inquiry & reform” Electro magnetic waves 05-02-2015 Radio waves Radio waves are used for communication & broadcasting For eg. FM transmissions use the frequencies from 88MHz to 108 MHz, satellite communications use 4000-6000 MHz & 11000-14000 MHz generally & so on. Mobile service providers also use the radio waves normally in the range of 900-1800 MHz Spectrum allocation & auction • Two operators cannot use the same frequency in the same region as there will be interference btw each other & both the services will get affected • Same frequencies can be used at two different places separated by sufficient distance so that there will not be any interference. This is called space diversity • The number of voice channels that can be supported depends on the bandwidth of the frequency spectrum allocated. Higher the bandwidth, more the number of channels that can be accommodated • This radio frequency spectrum is a limited resource & different services are allocated different frequencies • So basically the users are allocated a band of radio frequencies for their service & this radio frequency band is called spectrum • The operators use these frequencies to provide service & earn revenue. As revenue earned will be high there will be competition to get frequency band & hence auction is done with some regulations • For eg. private FM operators use the FM band , provide radio service & earn revenue from the advertisements. 150KHz bandwidth is sufficient for one FM station as so many FM stations can exist in the 88-108 MHz band allotted for FM radio service 05-10-2014 Indians invented the zero & the decimal system Stephen Hawking • explained the string theory with an attempt to integrate multiple loss of nature LIDAR stands for 'Laser Imaging, Detection & Ranging' • In archealogical survey to map and understand the surface characteristics FM- Frequency Modulation Spectrum of light Science Page 2 www.facebook.com/groups/abwf4india Facebook Group: Indian Administrative Service ( Raz Kr) RazKr [Live] - https://telegram.me/RazKrLive Spectrum of light 01-05-2014 Difference btw Induction stove & microwave oven • What is difference btw working principles of microwave oven & induction stove? Why are only stainless steel vessels preferred for the induction stove instead of copper, brass and aluminium, which are good conductors of heat? • In case of microwave oven, microwaves which are of low wave lengths (about 12 cm) but contain high energy, are produced through a device known as magnetron. The microwaves are reflected on to the cooking vessel where the food is stored • The high energy microwaves vibrate the molecules of the food at very high frequency (2500,000000/sec) which in turn produces high quantity of heat energy. The heating of food is more uniform as compared to other methods. • However, only non metallic containers can be used to store food inside the oven as metallic containers are likely to reflect back the micro waves • Also one has to take extra precautions while using the microwave oven as the high energy waves can harm the living cells of the body • In case of an induction stove, the heat energy is produced through induction effect. There is an electric coil below the top of induction stove. When varying (alternating) electric current is passed through the coil, a magnetic field is produced around it • When a steel or any other ferro-magnetic metal vessel is kept on the top of the induction stove, it produces eddy electric current in the vessel itself. Due to resistivity of the metal, when the electric current is passed in the vessel, it produces heat energy (as produced in an electric heater) which in turn heats up the food. However, limitation of the induction stove is that vessels which are of non ferromagnetic metal like copper, aluminium, or of glass cannot be used as there will be no eddy current in them 08-05-2014 What makes stainless steel non-magnetic whereas ordinary steel and iron are magnetic? We have to first understand how magnetic fields are generated around magnetic metals to answer this question. We know that within each atom, electrons spin on their axis that, in turn, causes magnetic field around them. Some electrons spin clockwise, some counter-clockwise. Generally they are paired so that the magnetic fields are cancelled. Iron which is a magnetic substance has three unpaired electrons. Each electron generates a magnetic field of its own. If all the fields pull in the same direction then you have a magnet. In other words, the magnetic fields are aligned in a magnet. In the case of stainless steel, there are several types of them. In general they are made of iron (Fe), carbon (C), and about 10 per cent chromium (Cr). Some contain Nickel (Ni). But other metals are added to obtain different properties. As stainless steel contains iron, a magnetic metal, one it would seem that it would be magnetic. However, when nickel (Ni) is added to stainless steel the result is a nonmagnetic form of stainless steel, called austenitic stainless steel. At the atomic level, all the iron atoms act as mini magnets that are aligned in the same direction. The net effect of this is that collectively the magnetic properties of all the iron atoms add up to produce the overall magnetisation of the material. This is known as ferromagnetism. But the addition of other elements to iron changes the properties. For instance, when chromium and nickel are added, the arrangement of atoms changes completely and this, in turn, affects the magnetic properties of iron. The nickel and chromium that are added to iron tend to cancel the magnetic fields and the net outcome is that stainless steel becomes a non-magnetic substance. 11-06-2014 Science Page 3 www.facebook.com/groups/abwf4india Facebook Group: Indian Administrative Service ( Raz Kr) RazKr [Live] - https://telegram.me/RazKrLive 11-06-2014 Mirage- an optical phenomenon caused by the bending of light as it passes from colder to warmer air. NRI scientist AJ Paulraj wins tech ‘Nobel’ Marconi Prize • Inventing & advancing MIMO (Multiple Input Multiple Output) technology, a key enabler of wireless broadband services that has revolutionized high speed delivery of multimedia across the world • Every wifi router & 4G phone today uses MIMO technology pioneered by him 31-01-2014 IISc to set up brain research centre • The Centre will specifically aim to find cure for neurodegenerative conditions accelerated by old age • Diseases such as dementia receive little attention although they are widespread, are devastating for patients & extremely challenging for families & caregivers • Neurodegenerative conditions such as dementia are only going to rise with increase in life expectancy. We need to look at risk factors & ways to help protect the brain better. Diabetes, for instance, has been linked to dementia • Given the diversity of India’s population & the complexity of these diseases, the scope for research is enormous • We are working towards creating a globally recognised, world-class research facility that will be at the cutting-edge of research on the human brain 26-03-2014 String-theorist wins G.D. Birla Award Rajesh Gopakumar Gets G.D. Birla Award for Scientific Research for 2013 Professor Gopakumar has made fundamental contributions to the understanding of string theory, quantum field theory and mathematics. 08-05-2014 Citizen science • Citizen science in India is still in its infancy • While it is not new that amateur scientists have made scientific observations that mattered, Internet usage and the ensuing possibility of involving huge numbers of citizens in data collection and analysis is relatively new in India. • Citizen science in western world is more mature than in India. • CS initiatives like Zooniverse, eBird, etc, have participation that runs into tens of thousands, and what’s more, the databases built up by these have found their way into numerous peer-reviewed publications. • Citizen Science initiatives are being treated with the seriousness due to scientific study. • Project redundancy and repetition being a danger of such large projects, project developers could “adapt, adopt or collaborate with already-proven projects.” • They also suggest that developers can look at new possibilities and opportunities for data collection, for instance during natural and manmade disasters, such as oil spills, wild fires or earthquakes. • They moot the important idea of networking CS projects around the world so that the research can contribute to a Science Page 4 www.facebook.com/groups/abwf4india Facebook Group: Indian Administrative Service ( Raz Kr) RazKr [Live] - https://telegram.me/RazKrLive • They moot the important idea of networking CS projects around the world so that the research can contribute to a better under standing of phenomena like climate change. 09-09-2014 ‘Mandatory for scientists to give lectures in schools’ • The Centre has decided to make it mandatory for scientists and