Current Affairs UPSC

  Growth and Changing Structure of Employment   Here we will look at two developmental indicators-growth of employment and GDP. Fifty years of planned development have been aimed at expansion of the economy through increase in national product and employment.   During the period 1960-2000, Gross Domestic Product (GDP) of India grew positively and was higher than the employment growth. However, there was always fluctuation in the growth of GDP. During this period, employment grew at a stable rate of about 2 per cent.   In the late 1990s: employment growth started declining and reached the level of growth that India had in the early stages of planning. During these years, we also find a widening gap between the growth of GDP and employment. His means that in the Indian economy, without generating employment, we have been able to produce more goods and services. Scholars refer to this phenomenon as jobless growth.   We have seen how employment has grown in comparison to GDP. Now it is necessary to know how the growth pattern of employment and GDP affected different sections of workforce. From this we will also be able to understand what types of employment are generated in our country.   Distribution of workforce by industrial sectors shows substantial shift from work to non-farm work.   In 1972-73, about 74 per cent of workforce was engaged in primary sector and in 1999-2000, this proportion has declined to 60 per cent. Secondary and service sectors are showing promising future for the Indian workforce. You may notice that the shares of these sectors have increased from 11 to 16 per cent and 15 to 24 per cent respectively.   The distribution of workforce in different status indicates that over the last three decades (1972-2000), people have moved from self-employment and regular salaried employment to casual wage work. Yet self- employment continues to be the major employment provider. Scholars call this process of moving from self-employment and regular salaried employment to casual wage work as casualisation of workforce. This makes the workers highly vulnerable.     Informalisation of Indian Workforce      One of the objectives of development planning in India, since India's independence, has been to provide decent livelihood to its people. It has been envisaged that the industrialization strategy would bring surplus workers from agriculture to industry with better standard of living as in developed countries. We have seen in the preceding section, that even after 55 years of planned development, three-fifth of India workforce depends on farming as the major source of livelihood.   Economics argue that, over the years, the quality of employment has been deteriorating. Even after working for more than 10-20 years, why do some workers not get maternity benefit, provident fund, gratuity and pension? Why does a person working in the private sector get a lower salary as compared to another person more...

  Stock Market in India     Stock Market (Specially in India Context)   A stock exchange is an organization which provides a platform for trading shares- either physical or virtual. The origin of the stock, market dates back to the year 1494, when the Amsterdam Stock Exchange was first set up. In a stock exchange, investors through stock brokers buy and sell shares in a wide range of listed companies. A given company may list in one or more exchanges by meeting and maintaining the listing requirements of the stock exchange.   In financial terminology, stock is the capital raised by a corporation, through the issuance and sale of shares. In common parlance, however, stocks and shares are used interchangeably. A shareholder is any person or organization which owns one or more shares issued by a corporation. The aggregate value of a corporation's issued shares, at current market prices, is its market capitalization. Stock broker buys and sells for an investor and does the work of arranging the transfer of stock from a seller to a buyer.     Importance of Stock Exchanges   ·            For efficient working of the economy and for the smooth functioning of the corporate form of organization, the stock exchange is an essential institution. ·            an efficient medium for raising long term resources for business ·            Help raise savings from the general public by the way of issue of equity debt capital ·            attract foreign currency ·            exercise discipline on companies and make them profitable ·            investment in backward regions for job generation ·            another vehicle for investors? savings     Stock Exchanges in India   The first company that issued shares was the VOC or Dutch East India Company in. the early 17th century (1602). Since then we have come a long way. With over 25m shareholders today, India has the third largest investor base in the world after the USA and Japan. Over 9,000 companies are listed on the stock exchanges, which are serviced   by   approximately   7,500 stockbrokers. The Indian capital market is significant in terms of the degree of development, volume of trading and its tremendous growth potential.   Stock exchanges provide an organized market for transactions m securities and other securities. There are 24 stock exchanges in the country, 21 of them being regional ones with allocated areas. Three other are set up in the reforms era, viz. National Stock Exchange (NSE), the Over the Counter Exchange India Limited (OTCEI) and Inter-connected Stock Exchange of India Limited (ISE) Important Stock Exchanges more...

 Stars and the Solar System   1.           The Moon    

• The moon is the brightest object in the night sky. The stars, the planets, the moon and many other objects in the sky are called celestial objects.
• The day on which the whole disc of the moon is visible is known as the full moon day. Thereafter, every night the size of the bright part of the moon appears to become thinner and thinner. On the fifteenth day the moon is not visible. This day is known as the new moon day. The next day, only a small portion of the moon appears in the sky. This is known as the crescent moon. Then again the moon grows larger every day. On the fifteenth day once again we get a full view of the moon.
• The various shapes of the bright part of the moon as seen during a month are called phases of the moon.
• The time period between one full moon to the next full moon is slightly longer than 29 days. In many calendars this period is called a month.
• Why phases of the moon occur? The moon does not produce its own light, whereas the Sun and other stars do. We see the moon because the sunlight falling on it gets reflected towards us.
• The moon revolves around the Earth. The Earth along with the moon, revolve around the Sun.
• The moon is a fascinating object for poets and story-tellers. But when astronauts landed on the moon, they found that the moon's surface is dusty and barren. There are many craters of different sizes. It also has a large number of steep and high mountains. Some of these are as high as the highest mountains on the Earth.
• The moon has no atmosphere and has no water. Sound can not travel when there is no medium. So we can not able to here any sound on moon.

  2.           The Stars    

• In fact, stars emit light of their own. The Sun is also a star.
• The Sun is nearly 15,00,00,000 kilometres (150 million km) away from the Earth. more...

Gravitation   1.           Gravitation    

• Take a piece of thread. Tie a small stone at one end. Hold the other end of the thread and whirl it round. Before the thread is released, the stone moves in a circular path with a certain speed and changes direction at every point. The change in direction involves change in velocity or acceleration.
• The force that causes this acceleration and keeps the body moving along the circular path is acting towards the centre. This force is called the centripetal (meaning 'centre- seeking’) force. In the absence of this force, the stone flies off along a straight line. This straight line will be a tangent to the circular path.
• The motion of the moon around the earth is due to the centripetal force. The centripetal force is provided by the force of attraction of the earth. If there were no such force, the moon would pursue a uniform straight line motion.
• It is seen that a falling apple is attracted towards the earth. Does the apple attract the earth? According to the third law of motion, the apple does attract the earth. But according to the second law of motion, for a given force, acceleration is inversely proportional to the mass of an object. The mass of an apple is negligibly small compared to that of the earth. So, we do not see the earth moving towards the apple. Extend the same argument for why the earth does not move towards the moon.
• In our solar system, all the planets go around the Sun. By arguing the same way, we can say that there exists a force between the Sun and the planets.
• From the above facts Newton concluded that not only does the earth attract an apple and the moon, but all objects in the universe attract each other. This force of attraction between objects is called the gravitational force.

  2.           Universal Law of Gravitation    

• Every object in the universe attracts every other object with a force which is proportional to the product of their masses and inversely proportional to the square of the distance between them. The force is along the line joining the centres of two objects. This law is given by more...

 Light   1.           Concave and Convex Mirror    

• Image formed by a plane mirror is always virtual and erect. The size of the image is equal to that of the object. The image formed is as far behind the mirror as the object is in front of it. Further, the image is laterally inverted.
• Concave mirrors are commonly used in torches, search-lights and vehicles headlights to get powerful parallel beams of light. They are often used as shaving mirrors to see a larger image of the face.
• The dentists use concave mirrors to see large images of the teeth of patients. Large concave mirrors are used to concentrate sunlight to produce heat in solar furnaces.
• We can see a full-length image of a tall building/tree in a small convex mirror.
• Convex mirrors are commonly used as rear-view (wing) mirrors in vehicles. These mirrors are fitted on the sides of the vehicle, enabling the driver to see traffic behind him/her to facilitate safe driving. Convex mirrors are preferred because they always give an erect, though diminished, image. Also, they have a wider field of view as they are curved outwards. Thus, convex mirrors enable the driver to view much larger area than would be possible with a plane mirror.

  2.           Refraction of Light    

• We might have observed that the bottom of a tank or a pond containing water appears to be raised. Similarly, when a thick glass slab is placed over some printed matter, the letters appear raised when viewed through the glass slab. Why does it happen?
• We seen a pencil partly immersed in water in a glass tumbler? It appears to be displaced at the interface of air and water.
• We might have observed that a lemon kept in water in a glass tumbler appears to be bigger than its actual size, when viewed from the sides.
• Let us consider the case of the apparent displacement of a pencil, partly immersed in water. The light reaching us from the portion of the pencil more...

 Heat   1.           Temperature and Heat    

• Heat is the form of energy transferred between two (or more) systems or a system and its surroundings by virtue of temperature difference.
• A measure of temperature is obtained using a thermometer. Many physical properties of materials change sufficiently with temperature to be used as the basis for constructing thermometers.
• The commonly used property is variation of the volume of a liquid with temperature.

  2.           Thermal Expansion    

• We observed that sometimes sealed bottles with metallic lids are so tightly screwed that one has to put the lid in hot water for ometime to open the lid. This would allow the metallic cover to expand, thereby loosening it to unscrew easily.
• In case of liquids, you may have observed that mercury in a thermometer rises, when the thermometer is put in a slightly warm water. If we take out the thermometer from the warm water the level of mercury falls again.
• Similarly, in the case of gases, a balloon partially inflated in a cool room may expand to full size when placed in warm water.
• A fully inflated balloon when immersed in cold water would start shrinking due to contraction of the air inside.
• It is our common experience that most substances expand on heating and contract on cooling. A change in the temperature of a body causes change in its dimensions. The increase in the dimensions of a body due to the increase in its temperature is called thermal expansion. The expansion in length is called linear expansion. The expansion in area is called area expansion. The expansion in volume is called volume expansion.
• Water exhibits an anomalous behavour; it contracts on heating between \[0{}^\circ C\] and \[4{}^\circ C.\] The volume of a given amount of water decreases as it is cooled from room temperature, until its temperature reaches \[4{}^\circ C.\]Below \[4{}^\circ C.\]the volume increases, and therefore the density decreases.
• This means that water has a maximum density at \[4{}^\circ C.\] This property has an important environmental effect: Bodies of water, such as lakes more...

 Sound   1.           Characteristics of a Sound Wave  

• Frequency tells us how frequently an event occurs.
• A violin and a flute may both be played at the same time in an orchestra. Both sounds travel through the same medium, that is, air and arrive at our ear at the same time. Both sounds travel at the same speed irrespective of the source. But the bounds we receive are different. This is due to the different characteristics associated with the sound. Pitch is one of the characteristics.
• How the brain interprets the frequency of an emitted sound is called its pitch. The faster the vibration of the source, the higher is the frequency and the higher is the pitch.
• A high pitch sound corresponds to more number of compressions and rarefactions passing a fixed point per unit time. Objects of different sizes and conditions vibrate at different frequencies to produce sounds of different pitch.
• The magnitude of the maximum disturbance in the medium on either side of the mean value is called the amplitude of the wave- For sound its unit will be that of density or pressure. The loudness or softness of a sound is determined basically by its amplitude.
• The amplitude of the sound wave depends upon the force with which an object is made to vibrate. If we strike a table lightly, we hear a soft sound because we produce a sound wave of less energy (amplitude). If we hit the table hard we hear a loud sound. Can you tell why? Loud sound can travel a larger distance as it is associated with higher energy.
• A sound wave spreads out from its source. As it moves away from the source its amplitude as well as its loudness decreases.
• The cavity or timber of sound is that characteristic which enables us to distinguish one sound from another having the same pitch and loudness. The sound which is more pleasant is said to be of a rich quality. A sound of single frequency is called a tone. The sound which is produced due to a mixture of several frequencies is called a note and is pleasant to listen to.
• The speed of sound is defined as the distance which a point on a wave, such as a compression or a rarefaction, travels per unit time.                                
• The amount of sound energy passing each second through unit area is called the intensity of sound. more...

 Force and Laws of Motion   1.           Galileo Galilei    

• Galileo Galilei was born on 15 February, 1564 in Pisa, Italy. Galileo, right from his childhood, had interest in mathematics and natural philosophy.
• Galileo enrolled himself for a medical degree at the University of Pisa in 1581 which he never completed because of his real interest in mathematics.
• In 1586, he wrote his first scientific book 'The Little Balance [La Balancitta]', in which he described Archimedes' method of finding the relative densities (or specific gravities) of substances using a balance.
• In 1589, in his series of essays - De Motu, he presented his theories about falling objects using an inclined plane to slow down the rate of descent.
• In 1592, he was appointed professor of mathematics at the University of Padua in the Republic of Venice. Here he continued his observations on the theory of motion and through his study of inclined planes and the pendulum.
• Galileo was also a remarkable craftsman. He developed a series of telescopes whose optical performance was much better than that of other telescopes available during those days. Around 1640, he designed the first pendulum clock.
• In his book 'Starry Messenger' on his astronomical discoveries, Galileo claimed to have seen mountains on the moon, the Milky Way made up of tiny stars, and four small bodies orbiting Jupiter. In his books 'Discourse on Floating Bodies' and 'Letters on the Sunspots', he disclosed his observations of sunspots.
• Using his own telescopes and through his observations on Saturn and Venus, Galileo argued that all the planets must orbit the Sun and not the earth, contrary to what was believed at that time.
• Galileo's discoveries in astronomy were equally revolutionary. In 1609, he designed his own telescope (invented earlier in Holland) and used it to make a number of startling observations: mountains and depressions on the surface of the moon; dark spots on the sun; the moons of Jupiter and the phases of Venus.
• He concluded that the Milky Way derived its luminosity because of a large number of stars not visible to the naked eye. In his masterpiece of scientific reasoning : Dialogue on the Two Chief World Systems, Galileo advocated the heliocentric theory of the solar system proposed by Copernicus, which eventually got universal acceptance.

  2. more...

 Atom and Nucleus   1.            Ernst Rutherford (1871-1937)    

• British physicist who did pioneering work on radioactive radiation. He discovered alpha-rays and beta-rays.
• Along with Federick Soddy, he created the modem theory of radioactivity. He studied the 'emanation' of thorium and discovered a new noble gas, an isotope of radon, now known as thoron.
• By scattering alpha-rays from the metal foils, he discovered the atomic nucleus and proposed the plenatery lyiodel of the atom. He also estimated the approximate size of the nucleus.

  2.            Nucleus        

• In every atom, the positive charge and mass are densely concentrated at the centre of the atom forming its nucleus. The overall dimensions of a nucleus are much smaller than those of an atom.
• Experiments on scattering of \[\alpha \]-particles demonstrated that the radius of a nucleus was smaller than the radius of an atom by a factor of about \[{{10}^{4}}\]. This means the volume ofa nucleus is about \[{{10}^{-12}}\] times the volume of the atom.
• In other words, an atom is almost empty. If an atom is enlarged to the size of a classroom, the nucleus would be of the size of pinhead. Nevertheless, the nucleus contains most (more than \[99.9\]per cent) of the mass of an atom.
• Measurement of atomic masses is carried out with a mass spectrometer, The measurement of atomic masses reveals the existence of different types of atoms of the same element, which exhibit the same chemical properties, but differ in mass. Such atomic species of the same element differing in mass are called isotopes. (In Greek, isotope means the same place, i.e. they occur in the same place in the periodic table of elements). It was found that practically every element consists of a mixture of several isotopes.
• The lightest element, hydrogen has three isotopes. The nucleus of the lightest atom of hydrogen, which has a relative abundance of \[99.98\]per cent, is called the proton.
• The other two isotopes of hydrogen are called deuterium and more...

 Pressure   1.           Mechanical Properties of Solids and Fluids    

• The property of a body, by virtue of which it tends to regain its original size and shape when the applied force is removed, is known as elasticity and the deformation caused is known as elastic deformation.
• However, if we apply force to a lump of putty or mud, they have no gross tendency to regain their previous shape, and they get permanently deformed. Such substances are called plastic and this property is called plasticity.
• Pressure is a scalar quantity. The SI unit of pressure is N m-2 has been named as pascal (Pa).
• A common unit of pressure is the atmosphere (atm), i.e. the pressure exerted by the atmosphere at sea level (1 atm \[=1.013\times {{10}^{5}}\] Pa).
• Density is a positive scalar quantity. A liquid is largely incompressible and its density is therefore, nearly constant at all pressures. Gases, on the other hand exhibit a large variation in densities with pressure.
• The density of water at 4°C (277 K) is \[1.0\times {{10}^{3}}\] kg m-3. The relative density of a substance is the ratio of its density to the density of water at 4°C.
• The pressure of the atmosphere at any point is equal to the weight of a column of air of unit cross sectional area extending from that point to the top of the atmosphere. At sea level it is \[1.013\times {{10}^{5}}\] Pa (1 atm).
• The mm of Hg and torr are used in medicine and physiology. In meteorology, a common unit is the bar and millibar.
• An open-tube manometer is a useful instrument for measuring pressure differences.
• In reality the density of air decreases with height. So does the value of g. The atmospheric cover extends with decreasing pressure over 100 km. We should also note that the sea level atmospheric pressure is not always 760 mm of Hg. A drop in the Hg level by 10 mm or more is a sign of an approaching storm.

  2.           Hydraulic Machines    

• Whenever external pressure is applied on any part of a fluid contained more...