•  
    +91-22 - 43484479
    +91-22 - 43484480

Toppers' Discussion Forum

All questions answered by Topper experts.
Question By

Thu August 28, 2014  

Ans: The Women marched to Versailles in October 1789 because of the following reasons: The poor harvests in 1788 and 1789 and the supplies of grain fell well short of their usual level, which resulted in the dramatic price rise of bread in 1789. During the early stages of the French Revolution, the high cost and limited supply of bread and other foodstuffs in 1789 proved an additional factor for the mobilization of the working poor in Paris and other cities. The food shortages in the popular markets of Paris fostered discontent and fear, forcing the women consumers to show their concern by marching to Versailles and calling upon the king, Louis XVI, to exercise his paternal role by securing more food for the people of Paris. The belief that the king was “the father of his people” was a traditional notion that the monarchy cultivated also cultivate to strengthen popular loyalty to the king. 

Wed August 27, 2014  

Ans: We are currently in the process of uploading the material for 'The Story of My Life'. 

Wed August 27, 2014  

Ans: The heat required to raise the temperature of a substance by 1° C is called the heat capacity of the substance. It depends upon the mass and the nature of the substance. As the amount of heat gained by a substance depends upon the nature of the substance and the chemical composition of the substance we define heat capacity of a substance more precisely as specific heat capacity (C) , which is the amount of heat required to raise the temperature of 1 kg of substance through 1 ° C. The quantity of heat absorbed or added to a body is directly proportional to its mass and change in the temperature of the body. 
 Syntax error from line 1 column 49 to line 1 column 73. Unexpected '<mstyle '.
 

Wed August 27, 2014  

Ans: Architecture in Harappan civilisation Architecture in modern world today People in the Harappan Civilisation made houses mostly of mud bricks, baked bricks and chiseled stones. Today, houses are made up of bricks, cement, glass, various metals like steel, iron etc. Cities of the ancient Harappan civilisation were surrounded and fortified by huge city walls. In present day, we hardly find any major city built with in walls. Inspite of the absence of technology in this age, the drainage system was well planned. Drains inside the houses were connected to drains on the streets and smaller drains led into the bigger drains. With various advancements made in technology, today, advanced drainage systems have geotextile filters that prevent fine grain particles form passing into the drain in order to avoid the clogging. The cities were planned in grid system where roads cut across each other at 90 0 . This feature is not present in modern day architecture. Houses were either of one or two storeys, with rooms built around a courtyard. We now find sky scrapers in most of the cities in the world which are equipped with various modern amenities. Architecture in Harappan civilisation Architecture in modern world today Harappans made houses mostly of mud bricks, baked bricks and chiseled stones. Today, houses are made up of bricks, cement, glass, various metals like steel, iron etc. Cities of the ancient Harappan civilisation were surrounded and fortified by huge city walls. In present day, we hardly find any major city built with in walls. Inspite of the absence of technology in this age, the drainage system was well planned. Drains inside the houses were connected to drains on the streets and smaller drains led into the bigger drains. With various advancements made in technology, today, advanced drainage systems have geotextile filters that prevent fine grain particles form passing into the drain in order to avoid the clogging. The cities were planned in grid system where roads cut across each other at 90 0 . This feature is not present in modern day architecture. Houses were either of one or two storeys, with rooms built around a courtyard. We now find sky scrapers in most of the cities in the world which are equipped with various modern amenities. Architecture in Harappan civilisation Architecture in modern world today People in the Harappan Civilisation made houses mostly of mud bricks, baked bricks and chiseled stones. Today, houses are made up of bricks, cement, glass, various metals like steel, iron etc. Cities of the ancient Harappan civilisation were surrounded and fortified by huge city walls. In present day, we hardly find any major city built with in walls. Inspite of the absence of technology in this age, the drainage system was well planned. Drains inside the houses were connected to drains on the streets and smaller drains led into the bigger drains. With various advancements made in technology, today, advanced drainage systems have geotextile filters that prevent fine grain particles form passing into the drain in order to avoid the clogging. The cities were planned in grid system where roads cut across each other at 90 0 . This feature is not present in modern day architecture. Houses were either of one or two storeys, with rooms built around a courtyard. We now find sky scrapers in most of the cities in the world which are equipped with various modern amenities.

Wed August 27, 2014  

Ans: (a) An electric fuse is a safety device which is used to limit the current in a domestic electric circuit. The use of a fuse safeguards the circuit and the appliances connected in that circuit from being damaged.   Its most important characteristic is that it is a short piece of wire made up of a material of high resistivity and low melting point; so that it may easily melt due to overheating when current in excess to the prescribed limit passes through it.   (b) The material generally used for constucting a good fuse is an alloy of lead and tin.   Note: Kindly ask the last question as a separate query.

Wed August 27, 2014  

Ans: Pineal gland still being considered as vestigial organ is not sure. Until the 1950s scientists regarded the pineal vestigial organ. Comparative anatomical studies had shown that the pineal gland has the same embryological origin as the parietal i.e. the third eye in other, less evolved vertebrates. For example, several lizards have a parietal eye seated in an opening at the top of their skulls. In amphibians, birds, and mammals, this parietal opening has closed, so the pineal gland remains inside the skull. Hence it has lost its function. But the pineal gland continues to secrete melatonin which has high significance. However its role in other vertebrates is unknown.

Wed August 27, 2014  

Ans: Dental amalgam is a mixture of mercury and a silver–tin alloy. Adavantages: The amalgam filings are strong and long-lasting than other types of filings. It is least expensive filling material. Disadvantages: Since it contains the element mercury it liberates very low levels of mercury that can be inhaled. Exposure to high levels of mercury vapour are associated with severe effects in the brain and the kidneys.    

Wed August 27, 2014  

Ans: 1.Speed of a moving object tells us how fast that object is moving but it does not tell us about the direction in which the object is moving. To get an idea about the exact position of the moving object we need to know the direction of motion also (i.e both speed and direction ). The velocity of the moving body implies both its speed and direction of motion.   Velocity of a body is the distance travelled by the body per unit time in a given direction.   i.e. Syntax error from line 1 column 49 to line 1 column 73. Unexpected '<mstyle '.    Distance travelled in a given direction is known as displacement and hence we can write velocity=Displacement / Time taken.   2.Magnitude means the relative size of the quantity i.e  just the measurement or the value without direction.  Speed has only magnitude but no specific direction whereas velocity has both magnitude and direction. Eg: Speed of a car is 25 km/hr. It is just the magnitude i.e 25 km/hr ( just the size or value indicating how fast the car is travelling ). On the other hand 25 km/hr towards north indicates the velocity of the car (with both magnitude (25 km/hr ) and direction(north) ).

Wed August 27, 2014  

Ans: Syntax error from line 1 column 2143 to line 1 column 2334. Unexpected '('.

Wed August 27, 2014  

Ans: G i v e n space square root of 2 S i n space A equals S i n space B space minus space S i n cubed space B space.... space 1 square root of 2 space C o s space A equals C o s space B space plus thin space C o s cubed space B space.....2  M u l t i p l y space 1 space b y space C o s space B space o n space b o t h space s i d e s comma space w e space g e t square root of 2 space S i n space A space C o s space B space equals space S i n B space C o s space B space open parentheses 1 minus space S i n squared space B close parentheses  S i n space A space C o s space B equals space fraction numerator S i n B space C o s cubed space B space over denominator square root of 2 end fraction  S i m i l a r l y space m u l t i p l y space 2 space b y space S i n space B space o n space b o t h space s i d e s comma space w e space g e t square root of 2 C o s space A space S i n space B equals S i n B space C o s space B open parentheses 1 plus cos squared space B close parentheses  C o s space A space S i n space B equals fraction numerator S i n B space C o s space B open parentheses 1 plus cos squared space B close parentheses over denominator square root of 2 end fraction  S i n space left parenthesis A minus B right parenthesis equals S i n space A space C o s space B space minus space C o s space A space S i n space B equals fraction numerator S i n B space C o s cubed space B space over denominator square root of 2 end fraction minus fraction numerator S i n B space C o s space B open parentheses 1 plus cos squared space B close parentheses over denominator square root of 2 end fraction S i n space left parenthesis A minus B right parenthesis equals fraction numerator minus S i n B space C o s space B over denominator square root of 2 end fraction equals fraction numerator minus S i n space 2 B over denominator 2 square root of 2 end fraction

Wed August 27, 2014  

Ans: Meristemiatic tissue is the region of active cell division. Cells are thin-walled and made up of cellulose. Cells are small and have prominent nuclei. They may be spherical, oval or polygonal in shape. Cells are compactly arranged and do not have intercellular spaces. Cells contain dense or abundant cytoplasm and a single large prominent nucleus. Vacuoles are small or absent. Meristematic tissue is Located at the tips of roots and stems, base of node, base of internode or at the base of the leaf. It is also present between the wood and bark of trees. Functions: Different types of cells are produced through division and differentiation of meristematic cells. The cells of meristematic tissue divide actively, resulting in growth (increase in thickness and length) of plants.

Wed August 27, 2014  

Ans: The Relation R is an equivalence relation if and only if it satisfies the properties, Reflexivity, Symmetry and Transitivity.   Reflexivity: a is related to a because a-a is zero and zero divisible by any number and hence R is reflexive.   Symmetry: Assume that a is related to b, and hence a-b is divisible by m   Since a and b are integers, we have, a minus b equals m k subscript 1 space a n d space b minus a equals m k subscript 2 comma space w h e r e space k subscript 1 space a n d space k subscript 2 space a r e space a n y space i n t e g e r s and hence both are divisible by m. Thus, R is Symmetric.   Transitivity: Iif a is related to b, we have, a minus b equals m k subscript 1 If b is related to c, we have, b minus c equals m k subscript 2 Now consider,  a minus c equals a minus b plus b minus c equals m k subscript 1 plus m k subscript 2 equals m open parentheses k subscript 1 plus k subscript 2 close parentheses Thus, a - c is divisible by m and hence a is related to c. Thus, R is transitive. Hence R is an equivalence relation.

Wed August 27, 2014  

Ans:  integral fraction numerator sin to the power of minus 1 space space end exponent square root of x space end root space space space minus cos space to the power of minus 1 end exponent square root of x over denominator sin to the power of minus 1 space space end exponent square root of x space end root space space space plus cos space to the power of minus 1 end exponent square root of x end fraction d x................. left parenthesis i right parenthesis  P u t space sin to the power of minus 1 space space end exponent square root of x space end root space space space equals space theta square root of x space end root space equals sin space theta x equals space sin squared theta d x space equals 2 sin space theta cos space theta d theta  cos space to the power of minus 1 end exponent square root of x equals cos to the power of minus 1 end exponent left parenthesis sin space space theta right parenthesis equals cos to the power of minus 1 end exponent left parenthesis cos left parenthesis 90 minus theta right parenthesis right parenthesis equals 90 space minus theta P u t t i n g space v a l u e s space o f space sin to the power of minus 1 space space end exponent square root of x space end root a n d space cos space to the power of minus 1 end exponent square root of x space space space i n space left parenthesis i right parenthesis space w e space g e t comma  integral fraction numerator theta minus 90 plus theta over denominator theta plus 90 minus theta end fraction 2 sin space theta cos space theta d theta equals integral fraction numerator 2 theta minus 90 over denominator 90 end fraction sin space 2 theta space d theta equals integral fraction numerator 2 theta sin space 2 theta over denominator 90 end fraction minus 1 over 45 integral sin space 2 theta d theta space plus integral sin space 2 theta d theta  equals integral fraction numerator theta sin space 2 theta over denominator 45 end fraction minus 1 over 45 integral sin space 2 theta d theta minus fraction numerator cos space 2 theta over denominator 2 end fraction   equals minus fraction numerator theta cos space 2 theta over denominator 90 end fraction plus fraction numerator cos 2 theta over denominator 90 end fraction minus fraction numerator cos space 2 theta over denominator 2 end fraction plus c   equals minus fraction numerator sin to the power of minus 1 space space end exponent square root of x space end root cos space left parenthesis 2 sin to the power of minus 1 space space end exponent square root of x space end root right parenthesis over denominator 90 end fraction minus fraction numerator 22 cos left parenthesis 2 sin to the power of minus 1 space space end exponent square root of x space right parenthesis end root over denominator 45 end fraction plus c

Tue August 26, 2014  

Ans: G i v e n space t h a t space p e r i m e t e r space i s space 16 space u n i t s. P e r i m e t e r space o f space t h e space r e c tan g u l a r space w i n d o w space s u r m o u n t e d space b y space a n space e q u i l a t e r a l space t r i a n g l e space equals 2 l plus b plus b plus b equals 16 rightwards double arrow 3 b equals 16 minus 2 l rightwards double arrow b equals fraction numerator 16 minus 2 l over denominator 3 end fraction A r e a space i s space g i v e n space b y A equals l b plus fraction numerator square root of 3 over denominator 4 end fraction b squared rightwards double arrow A equals l cross times fraction numerator 16 minus 2 l over denominator 3 end fraction plus fraction numerator square root of 3 over denominator 4 end fraction open parentheses fraction numerator 16 minus 2 l over denominator 3 end fraction close parentheses squared fraction numerator d A over denominator d l end fraction equals fraction numerator 16 minus 4 l over denominator 3 end fraction plus fraction numerator square root of 3 over denominator 4 end fraction open parentheses fraction numerator 16 minus 2 l over denominator 3 end fraction close parentheses open parentheses minus 2 close parentheses F o r space m a x i m u m comma space fraction numerator d A over denominator d l end fraction equals 0 fraction numerator 16 minus 4 l over denominator 3 end fraction plus fraction numerator square root of 3 over denominator 4 end fraction cross times 2 cross times open parentheses fraction numerator 16 minus 2 l over denominator 3 end fraction close parentheses open parentheses minus 2 close parentheses equals 0  fraction numerator 16 minus 4 l over denominator 3 end fraction equals fraction numerator square root of 3 over denominator 4 end fraction open parentheses fraction numerator 16 minus 2 l over denominator 3 end fraction close parentheses open parentheses 4 close parentheses fraction numerator 16 minus 4 l over denominator 3 end fraction equals square root of 3 open parentheses fraction numerator 16 minus 2 l over denominator 3 end fraction close parentheses 16 minus 4 l equals square root of 3 open parentheses 16 minus 2 l close parentheses 16 minus 16 square root of 3 equals 4 l minus 2 square root of 3 l 16 open parentheses 1 minus square root of 3 close parentheses equals 2 l open parentheses 2 minus square root of 3 close parentheses 8 open parentheses 1 minus square root of 3 close parentheses equals l open parentheses 2 minus square root of 3 close parentheses l equals fraction numerator 8 open parentheses 1 minus square root of 3 close parentheses over denominator 2 minus square root of 3 end fraction W e space k n o w space t h a t space b equals fraction numerator 16 minus 2 l over denominator 3 end fraction S u b s t i t u t i n g space t h e space v a l u e space o f space l equals fraction numerator 8 open parentheses 1 minus square root of 3 close parentheses over denominator 2 minus square root of 3 end fraction comma space w e space c a n space f i n d space t h e space v a l u e space o f space b

Tue August 26, 2014  

Ans: 1. Kepler's laws govern the motion of planets around the sun and is known as Kepler's laws of planetary motion.   Kepler's first law:
The planets move in elliptical orbits around the sun, with the sun at one of the two foci of the elliptical orbit. i.e. Planets revolve around sun in an orbit.The orbit of a planet around sun is an ellipse and not exact circle. Ellipse is a geometrical figure like an elongated circle.An elliptical path has two foci and sun is located at one of the foci of the ellipse and is not at the centre.    

Kepler's Second law:
Each planet revolve around the sun in such a way that the line joining the planets to the sun sweeps out equal areas in equal intervals of time. As the line joining planets and sun sweeps equal areas in equal interval of time ,a planet moves faster when it is closer to the sun and moves slowly when it is farther from the sun.This implies that a planet does not move with constant speed around sun. The speed is greater when the planet is nearer the sun and less when the planet is farther away from the sun.
Kepler's Third law:
The cube of the mean distance of a planet from the sun is directly proportional to the square of time it takes to move around the sun.   Syntax error from line 1 column 49 to line 1 column 73. Unexpected '<mstyle '.
Kepler’s laws are applicable to all planets in the solar system.   2. When a body is dropped from some height , a uniform acceleration is produced in it by the gravitational pull of earth and this acceleration does not depend upon the mass of the falling object.So when a body is dropped freely, it falls with an acceleration of 9.8 m/s 2  .Hence the acceleration of the rubber ball and metal ball when dropped from the top of a buiding will be 9.8 m/s 2 .The acceleration produced in the freely falling bodies is same for all the bodies and it does not depend on the mass of the falling body.

Tue August 26, 2014  

Ans: You can write subjective answers on a paper. Once you complete the test, you can verify your answers with the solutions provided. In your user ID you have an option of making notes to which will help you to jot down important points while verifying your answers.

Tue August 26, 2014  

Ans: Amphoteric oxides are oxides of metals which show both acidic as well as basic behaviour. Such metallic oxides react with acids as well as base to produce salt and water. Eg: Aluminium oxide and Zinc oxide.

Tue August 26, 2014  

Ans: Hybridisation Overlapping It is defined as the process by which atomic orbitals of slightly different energies combine to form a new set of equivalent orbitals known as hybrid orbitals. It is defined as the process by which different types of bond are formed between the orbitals of two or more atoms. This term is used in reference to one atom. Orbital overlapping is used in reference to two or more atoms. There is no bond formation and involves just redistribution of energy. There is bond formation. Hybrid orbitals are named by considering the type and number of atomic orbitals from which they arose. Single, double and triple bond are decided from the overlap of s and p orbitals. Hybridisation provides exact explanation for the structure of compounds like Methane (CH 4 ). Concept of maximum orbital overlap fails to explain structure of compounds like Methane (CH 4 ).

Tue August 26, 2014  

Ans: Axioms & Postulates are basic assumptions and accepted without detailed demonstration. All other theorems must be proven with the help of basic assumptions. In many subjects related to science and mathematics, they lay certain additional hypotheses which are accepted without proof. Such a hypothesis is termed as postulate. On the other hand, axioms are common to lot of subjects whereas postulates of each subject are different. Example: Axioms: Things which are equal to the same thing are also equal to one another(Same in all subjects).  Postulates: It is possible to draw a straight line from any point to any other point(Only Geometry)

Tue August 26, 2014  

Ans: The time interval between 24 to 52 seconds, body travel fastest between time interval 42 to 52 seconds. The velocity of the body between this time interval is 10 m/s which is highest velocity between this time interval Thus, the body travels fastest between 42 to 52 seconds time interval.
Top Contributors this Month
#1
2572 Comments 6143 Likes
#2
1309 Comments 4147 Likes
#3
255 Comments 2168 Likes
#4
699 Comments 1527 Likes