Class 11 Engineering Physics - Physical World

Though India now has a large base in science and technology, which is fast expanding, it is still a long way from realising its potential of becoming a world leader in science. Name some important factors, which in your view have hindered the advancement of science in India.

Some important factors in our view which have hindered the advancement of science in India are:

Proper funds are not arranged for the development of research work and laboratories. The labs and scientific instruments are very old and outdated.
Most of the people in India are uneducated and highly traditional. They don't understand the importance of Science.
There is no proper employment opportunity for the science educated person in India.
There are no proper facilities for science education in schools and colleges in India.

"Politics is the art of the possible." Similarly, "Science is the art of the soluble." Explain this beautiful aphorism on the nature and practice of science.

Science is a systematized study of observations. A scientist critically analyses these observations and comes out with certain laws. For example, Tycho Brahe worked for twenty long years to make observations on planetary motions. It is from this huge reservoir of observations that Johannes Kepler formulated his three famous laws of planetary motion.

It is well known that to win over votes, politicians would make anything and everything possible even when they are least sure of the same and in Science the various natural phenomena can be explained in terms of some basic laws. So as 'Politics is the art of possible' similarly 'Science is the art of the soluble'

Match the following:
S.No Scientists Inventions
1 Michael Faraday First battery
2. George Simon Ohm Radioactivity
3. Volta Dynamo
4. Henry Becquerel Ohm's law

The following are the inventions made by the scientists:

1. Micheal Faraday $$\Longrightarrow$$ Dynamo

Micheal Faraday invented dynamo. A dynamo is a device that uses electromagnetism to to create a direct current of electrical power.

2. George Simon Ohm $$\Longrightarrow$$ Ohm's law

Ohm's law states that electric current in a conductor is proportional to voltage and inversely proportional to resistance.

3. Volta $$\Longrightarrow$$ First battery

Volta invented the first true battery, which came to be known as the voltaic pile.

4. Henry Becquerel $$\Longrightarrow$$ Radioactivity

What is Physics?

Physics is the study of matter, energy, and the interaction between them.

Broadly it is classified as-

1. Mechanics- This focuses on the behavior of objects and the forces that act upon them.

2. Thermodynamics- This is the study of heat, temperature, and energy.

3. Optics- This is the study of light waves.

4. Acoustics- This is the study of sound waves.

5. Electromagnetism- This is the study of electric and magnetic forces.

What is the composition of air?

Nitrogen, oxygen, carbon dioxide, water vapor, and a few additional gases make up air. It may also contain some dust particles.

Air is made up of $$78$$% nitrogen, $$21$$% oxygen, $$1$$% carbon dioxide, water vapors, and a few other gases.
Air is a mixture of many gases. The components of air are nitrogen, oxygen, noble gases, carbon dioxide, water vapour, smoke, and dust particles. The main gases present in the air are nitrogen (78%), oxygen (21%), and the other gases 1%. Among the others are noble gases (0.95%), carbon dioxide (0.03%), and varying amounts of water vapour (depending upon the weather).

Which scientist gave the theory of Ionization in Physics ?

Meghnad Saha.

Name the Indian scientist who gave Bose-Einstein Statistics.

Professor Satyendra Nath Bose.

Who wrote the Book 'The History of Hindu Chemistry' ?

The inventor of Indian Chemical Industry Prafulla Chandra Ray wrote the famous book The History of Hindu Chemistry.

Which mathemetician gave title 'Ganak Chakra ChuramanV to Brahmagupta ?

Bhaskara.

India's first cyclotron was established under which scientist supervision ?

Mehnad Saha.

Name the book written by Sushruta ?

Sushrut Samhita.

Search and you will find.
There are about _______ stars in our galaxy.

There are about billion stars in our galaxy.

Who started the Hindu decimal System ?

Bhaskaracharya - I

Who had set up the first nuclear reactor in India ?

Homi Jehangir Bhabha.

Define Science.

Science is systematic knowledge, based on experimental observations for a query or investigation.

Which coment was named after astronomer M.K. Venu Bappu ?

Bappu- Boak - Newquark.

When World Yoga Day is celebrated ?

$$21$$st June.

Define Abstract Science.

The branch of Science in which we study Mathematics and Statistics is known as Abstract Science.

Name the famous Indian Universities in $$400$$ B.C.

Nalanda , Varanasi and Taxila.

Who gave the Ionization formula ?

Meghnad Saha

Name the oldest book of Mathematical and Statistics.

Aryabhattiya Bhasya

Write the name of the Arabian translation of book Sushtra Samhita ?

Sashun-e-Hindi
Kitab-e-Susrad

ISRO was earlier known by which name ?

Indian National Committee for Space Research (INCOSPAR)

Who gave the relation between circumference and diameter of circle ?

Aryabhatta.

Name India's self-sustaining missile developing programme ?

Brahmos.

Which scientist was also a member of Parliament ?

Professor Satyendra Nath Bose.

Where are some people living outside the earth ?

At International Space Station, some people are living outside the earth.

What is the meaning of the term 'alien' ?

Extra terrestrial life is called alien. Scientists assume that molecules which created life on the earth are available in plenty in different parts of the universe. Hence, possibility of alien life is pretty high. The alien life may be more developed or even less developed compared to variety of life on earth.

Who wrote the book Lilawati based on Arithmetic ?

Bhaskaracharya.

Who discovered gymnosperms ?

Dr. Birbal Sahni

Which scientist contributed towards establishment of Keyla Dev Bird Sanctuary in Bharatpur?

Dr. Salim contributed towards establishment of Keyla Dev Bird Sanctuary in Bharatpur.

Which reactors were established under the direction of Dr. B.habha?

Apsara, Cirus and Gerlina

What was the first job for Dr. C. V. Raman?

Deputy Accountant General under government of India

Sushruta was a descendent of which sage?

Vishwamitra

Who was the guru of Sushruta?

Sushrut compiled the knowledge and teachings of his guru Divodas Dhanvantari, King of Kashi.

Who is called as the 'Father of Indian Nuclear Programme' ?

Dr. Homi Jehangir Bhabha

Which book was written by Charak?

Charaka Samhita and Sutra sthana.

Which book was written by Sushruta?

Sushruta Samhita

Suppose that you tum on the heater in your room and all of the lights in your room go out. Give a possible reason why the lights went out.

One possible reason is that there is a short circuit in the heater. Another possible reason is that the heater, along with any other devices attached to the circuit, overloads the circuit and trips the breaker.

Some of the most profound statements on the nature of science have come from Albert Einstein, one of the greatest scientists of all time. What do you think did Einstein mean when he said : "The most incomprehensible thing about the world is that it is comprehensible"?

The Physical world around us is full of different complex natural phenomena so the world is in-comprehensible. But with the help of study and observations it has been found that all these phenomena are based on some basic physical laws and so it is comprehensible.

"Every great physical theory starts as a heresy and ends as a dogma." Give some examples from the history of science of the validity of this incisive remark.

Dogma is an established opinion, which is questioned by only a few, while heresy means anything, which is against the established belief, few that creates ripples in the minds of the intelligent. For example, Thomas Young's wave theory of light started as a heresy and finally ended as a 'dogma', while Einstein and others replaced it by the quantum theory of light.

The statement above is true. Validity of this incisive remark can be validated from the example of moment of inertia. It states that the moment of inertia of a body depends on its energy. But according to Einstein's mass-energy relation ($$E = mc^2$$), energy depends on the speed of the body.

No physicist has ever "seen" an electron. Yet, all physicists believe in the existence of electrons. An intelligent but superstitious man advances this analogy to argue that 'ghosts' exist even though no one has 'seen' one. How will you refute his argument ?

No physicist has ever seen an atom but there are practical evidences and theories like Bohr's Atomic model, Rutherford's scattering experiment, etc. which prove the presence of electron. Their size is small, but we can test their existence by various methods like hydrogen spectrum.
On the other end there is no phenomena which can be explained on the basis of existence of ghosts.
So there is no comparison between the two given cases

India has had a long and unbroken tradition of great scholarship - in mathematics, astronomy, linguistics, logic and ethics. Yet, in parallel with this, several superstitious and obscurantistic attitudes and practices flourished in our society and unfortunately continue even today - among many educated people too. How will you use your knowledge of science to develop strategies to counter these attitudes ?

(i) In order to popularize scientific explanations of everyday phenomena, mass media like radio, television and newspaper should be used.

(ii) School books should include explanations regarding day-to-day experiences in life.

(iii) Students and youngsters should be encouraged to try and offer scientific explanation for many a so-called perplexing events and beliefs.

Poverty and illiteracy are the two major factors which make people superstitious in India. So to remove the superstitious and obscurantist attitude we have to first overcome these factors. Everybody should be educated, so that one can have scientific attitude. Knowledge of science can be put to use to prove people's superstitious wrong by showing them the scientific logic behind everything happening in our world.

"It is more important to have beauty in the equations of physics than to have them agree with experiments." The great British physicist P. A. M. Dirac held this view.Criticize this statement. Look out for some other equations and results , which strike you beautiful.

An equation which agrees with experiment must also be simple and hence beautiful. We have some simple and beautiful equations in Physics such as
$$E = mc^2$$ (Energy of light)
$$E = h\nu$$ (Energy of a photon)
$$KE =$$ $$\cfrac{1}{2}mv^2$$ (Kinetic energy of a moving particle)
$$PE = mgh$$ (Potential energy of a body at rest)
$$W = F.d$$ (Work done)
All have the same dimensions. One experiment shows dependency of energy on speed, the other shows dependency on frequency & displacement.
That's the beauty of equations in Physics coming from different experiments.

Write in about 1000 words a fiction piece based on your speculation on the science and technology of the twenty-second century.

Let us imagine a spaceship moving towards a distant star, 500 light years away. Suppose this is propelled by solar power fed into the electric motor consisting of super-conducting wires. In space, suppose there is a particular region, which has such a high temperature that destroys the super-conducting property of the electric wires of the motor. At this stage, another spaceship filled with matter and anti-matter comes to the rescue of the first ship and the first ship continues on its journey.

Attempt to formulate your 'moral' views on the practice of science. Imagine yourself stumbling upon a discovery, which has great academic interest but is certain to have nothing but dangerous consequences for the human society. How will you resolve your dilemma ?

A scientist aims at truth. A scientific discovery reveals the truth of nature. So, any discovery, useful or dangerous to mankind, must be made public. Every discovery can be put to both positive and negative use. It is left to the mankind to use it for the betterment of the people, society, to improve the quality of living or to use it for destruction. A discovery, which appears dangerous today, may become useful to mankind sometime later. In order to prevent misuse of scientific technology, we must build up public opinion against the misuse of a scientific discovery. Scientists should in fact take up two roles - to discover truth and to prevent its misuse.

It is often said that the world is witnessing now a second industrial revolution, which will transform the society as radically as did the first. List some key contemporary areas of science and technology, which are responsible for this revolution.

Some of the key contemporary areas of science and technology which may transform the society radically are:
1. Development of super fast computers
2. Internet and tremendous advancement in information technology
3. Development in Biotechnology
4. Development of super-conducting materials at room temperature.
5. Development of robots.

Science, like any knowledge, can be put to good or bad use, depending on the user. Given below are some of the applications of science. Formulate your views on whether the particular application is good, bad or something that cannot be so clearly categorised :
(a) Mass vaccination against small pox to curb and finally eradicate this disease from the population. (This has already been successfully done in India).
(b) Television for eradication of illiteracy and for mass communication of news and ideas.
(c) Prenatal sex determination
(d) Computers for increase in work efficiency
(e) Putting artificial satellites into orbits around the Earth
(f ) Development of nuclear weapons
(g) Development of new and powerful techniques of chemical and biological warfare).
(h) Purification of water for drinking
(i) Plastic surgery
(j ) Cloning

(a) Mass vaccination against small pox to curb and finally eradicate this disease from the population. (This has already been successfully done in India).- Good
Virus kills many people while some people are left with disabilities.
(b) Television for eradication of illiteracy and for mass communication of news and ideas. - Good
Good for removal of illiteracy and mass communication
(c) Prenatal sex determination - Bad
Can lead to gender ratio skewness and inequalities in society
(d) Computers for increase in work efficiency - Good
Improving the efficiency of work and globalization
(e) Putting artificial satellites into orbits around the Earth- Good
No. of uses like transmission etc. not possible by conventional methods
(f ) Development of nuclear weapons - Bad
Can result in mass destruction of people, buildings and factories.
(g) Development of new and powerful techniques of chemical and biological warfare. - Bad
All are methods of destroying lives and can be misused.
(h) Purification of water for drinking - Good
Need of the hour. Can stop many dangerous diseases and ensuring health.
(i) Plastic surgery - Good
For improving the disfigured parts of body.
(j ) Cloning- Good
With reference to medical application for curing ailments

Though the statement quoted above may be disputed, most physicists do have a feeling that the great laws of physics are at once simple and beautiful. Some of the notable physicists, besides Dirac, who have articulated this feeling, are : Einstein, Bohr, Heisenberg, Chandrasekhar and Feynman. You are urged to make special efforts to get access to the general books and writings by these and other great masters of physics. (See the Bibliography at the end of this book.) Their writings are truly inspiring !

There is no doubt that great laws of physics are at once so simple and beautiful and are easy to grasp. For example, let us look at some of these :
(i) E = $$mc^2$$ is a famous Einstein's mass energy equivalence relation which has a great impact not only on the various physical phenomenon but also on the human lives.
(ii) Plank's quantum condition i.e. E = h$$\nu$$ is also a simple and beautiful equation and it is a great law of Physics.
iii) $$\sigma$$x . $$\sigma$$p > h / 4$$\pi$$ is Heisenberg's Uncertainity Principle which is also very simple, beautiful and interesting. It is a direct consequence of the dual nature of matter.

(iv) $$\lambda$$= h/p is also a famous equation in Physics known as de-Broglie equation. It is again simple and beautiful.

Though the law gives women equal status in India, many people hold unscientific views on a woman's innate nature, capacity and intelligence, and in practice give them a secondary status and role. Demolish this view using scientific arguments, and by quoting examples of great women in science and other spheres; and persuade yourself and others that, given equal opportunity, women are on par with men.

Some people in our society have the view that women do not have the innate nature, capacity and intelligence.
To demolish this view there are many examples of women who have proven their abilities in Science and other fields.
Madam Curie, Mother Teresa, Indira Gandhi, Marget Thatcher, Rani Laxmi Bai, Florence Nightingale are some examples. So in this era women are definitely not behind man in any field.

The shells of crabs found around a particular coastal location in Japan seem mostly to resemble the legendary face of a Samurai. Given below are two explanations of this observed fact. Which of these strikes you as a scientific explanation ?
(a) A tragic sea accident several centuries ago drowned a young Samurai. As a tribute to his bravery, nature through its inscrutable ways immortalised his face by imprinting it on the crab shells in that area.
(b) After the sea tragedy, fishermen in that area, in a gesture of honour to their dead hero, let free any crab shell caught by them which accidentally had a shape resembling the face of a Samurai. Consequently, the particular shape of the crab shell survived longer and therefore in course of time the shape was genetically propagated. This is an example of evolution by artificial selection.

Explanation (b) is correct is a scientific explanation of the observed fact as it is backed by the scientific theory of 'evolution by artificial selection'.

The industrial revolution in England and Western Europe more than two centuries ago was triggered by some key scientific and technological advances. What were these advances?

More than two centuries ago, England and Western Europe started using machine that led to the industrial revolution
Some of the important inventions were
1 .Steam engine
2 .Electricity
3 .Theory of gravitation
4. Explosives
5. Cotton Jenny
6. Power Loom
7. Blast Furnace
Steam engines helped them in the field of heat and thermodynamics, theory of gravitation in field of motion and making guns and cannons. These progresses brought about industrial revolution in England and Western Europe.

Textbooks on science may give you a wrong impression that studying science is dry and all too serious and that scientists are absent-minded introverts who never laugh or grin. This image of science and scientists is patently false. Scientists, like anyother group of humans, have their share of humorists, and many have led their lives with a great sense of fun and adventure, even as they seriously pursued their scientific work. Two great physicists of this genre are Gamow and Feynman. You will enjoy reading their books listed in the Bibliography.

It is not an exercise as such but is a statement of fact. We can add the name of other scientist who were humorists along with being Physicists. They are C. V. Raman, Homi Jahangir Bhabha, Einstein and Bohr. India have several politicians like M. M. joshi, V. P. Singh etc. who are physicists. President A. P. J. Kalam is also a great nuclear scientist.

Write about your favourite scientist/physicist.

$$Sir \ Isaac\ Newton$$ was an english mathematician, astronomer and physicist who laid the foundations of $$classical\ mechanics$$. Newton also made seminal contributions to $$optics$$, and developing the infinitesimal $$calculus$$.

Newton also built the first practical $$reflecting\ telescope$$ and developed a sophisticated theory of colour based on the observation that a prism decomposes white light into the colours of the $$visible\ spectrum$$. He also formulated an empirical $$law\ of\ cooling$$, made the first theoretical calculation of the $$speed\ of\ sound$$.

What is the contribution of S. Chandra sekhar to physics?

S. Chandrasekhar was an Indian-born American astrophysicist who, with William A. Fowler, won the 1983 Nobel Prize for Physics for key discoveries that led to the currently accepted theory on the later evolutionary stages of massive stars.

By the early 1930s, scientists had concluded that after converting all of their hydrogens to helium stars lose energy and contract under the influence of their own gravity. These stars, known as white dwarf stars, contract to about the size of Earth, and the electrons and nuclei of their constituent atoms are compressed to a state of extremely high density. Chandrasekhar determined what is known as the Chandrasekhar limit—that a star having a mass more than 1.44 times that of the Sun does not form a white dwarf but instead continues to collapse, blows off its gaseous envelope in a supernova explosion, and becomes a neutron star. An even more massive star continues to collapse and becomes a black hole. These calculations contributed to the eventual understanding of supernovas, neutron stars, and black holes.

He did important work on energy transfer by radiation in stellar atmospheres and convention on the solar surface. He also attempted to develop the mathematical theory of black holes, describing his work in The Mathematical Theory of Black Holes (1983).

His other books include An Introduction to the Study of Stellar Structure (1939), Principles of Stellar Dynamics (1942), Radiative Transfer (1950), Hydrodynamic and Hydromagnetic Stability (1961), Truth and Beauty: Aesthetics and Motivations in Science (1987), and Newton’s Principia for the Common Reader(1995).

A crow-bar of length $$2.0$$m is used as a machine to lift a box of $$100$$ kgf by placing a fulcrum at a distance of $$0.1$$m from the box. Calculate the effort required.

Length of crow bar = 2m

length of load arm = 0.1M

length effort arm = length of crow bar -length of load arm

$$ = 2-0.1 = 1.9m $$

so, velocity ratio = length of effort arm/length of load arm = 1.9/0.1 = 19

use formula, velocity ratio = load/effort

19 = 100kgf/effort

effort = 100/19= 5.26 kgf

hence,5.26 effort is required.

Explain the process of twinkling of stars ?

The phenomenon that causes stars to twinkle is atmospheric refraction. That is, the air above us is a big ocean of not very dense fluid that has a small bending effect on light that passes through it. If it were perfectly still, the light from a star would follow a path that stays put, and the star's image would appear stable.

But the atmosphere is always moving; winds in every level of it cause slight density differences to move around, and different densities bend light by different amounts. And so the light rays from a star zig and zag as they head toward your eyes. That makes them appear to twinkle. The reason this happens for stars and not planets or other larger, "extended" objects, though, is that a star's apparent (angular) size is so very, very tiny. It is what is called in optics, a "point source."

When there's a little bit more of an apparent disk (these are measured in angle, and we're talking in the arc-second range and smaller), then it takes a lot more bending of the incoming light for the rays coming from all the parts of that disk to get bent away from your direction so that the (extended) object would appear to "blink" momentarily, and so, appear to twinkle. And it doesn't take much of an apparent disk to prevent twinkling.

But it also depends on what's happening in the air above you at any particular time, too. On some clear nights, there will be a lot of roiling in the atmosphere, and stars will twinkle more. Other clear nights, when the upper air is calm, twinkling will all but stop.

The whole effect is sometimes likened to what you see on the bottom of a swimming pool in bright sunlight. If the surface of the water is pretty wavy, there will be a lot of moving light and dark patterns on that pool floor. If nobody's been in the water for a while, and there's no wind, the surface gets smooth, and the moving patterns disappear.

What are study in Astrophysics ?

Astrophysics is a branch of space science that applies the laws of. physics and chemistry to explain birth, life, and death of stars, planets, galaxies, nebulae and other objects in the Universe. We also study the temperature of stars, their internal structure, and composition in Astrophysics.

Name the branch of Science in which Botany of the past period is studied.

Paleo-botany.

How Bose-Einstein Condensation can be formed ?

When a gas of Bose particles is cooled down to temperatures very close to absolute zero, then the kinetic energy of the particles decreases to a negligible amount and they condense to the lowest energy level state. This state is called as Bose-Einstein Condensation.

Write the two important works done by Bhaskaracharya-I.

Bhaskaracharya I gave the Pell’s equation $$ 8x$$ ? $$ + 1 = y^2 $$. In this equation $$ x = 1 $$and $$ y = 3$$ which can be written $$(x, y) = (1, 3)$$ , we can solve many equations like $$ (x, y) = (6, 17)$$.
For many centuries, the approximate value of % was considered 14. But Bhaskara-I did not accept this value and believed that n has an irrational value which later proved to be true. Some of the contributions of Bhaskara I to mathematics are: Numbers and symbolism, the categorization of mathematics, the names and solution of the first degree equations, quadratic equations, cubic equations and equations which have more than one unknown value, symbolic algebra, the algorithm method to solve linear indeterminate equations which was later suggested by Euclid, and formulated certain tables for solving equations that occurred in astronomy.

Write name of eight charans of Yoga given by Saint Patanjali.

1.Yama: It symbolises self-discipline. There are five Yama, i.e. Non-violence, Satya, Astay, Brahmacharya and Aparigraha.
2.Niyama: There are five rules.

The purity of mind and body.
Contentment
Self-evaluation
Devotion or complete surrender to God
Rigorous penance

3. Asana (Yogic postures)
4. Pranayama (Regulated breath)
5. Pratyahara (Sense detachment)
6. Dharma (Inner abstraction)
7. Dhyana (Meditation)
8. Samadhi (State of bliss)

All these elements of eightfold path are the universal commandants for all human beings. In fact, Yoga is not only the physical concept but more than that, it controls the mind, body and the entire human actions and reactions.

Professor Satyendra Nath Bose made the eye drop by the use of which chemical ?

Pr. S.N. Bose make a chemical by changing the internal structure of the sulphonamide molecule, which is now used as an eye drop.

When was Mars-Orbital Mission launched ?

$$24$$ th September $$2014$$.

Who first performed plastic surgery of nose ?

Sushruta.

The researches of Dr. Birbal Sahni are proved to be useful in which fields ?

Dr. Birbal Sahni was an Indian paleo-botanist. He studied the fossils of the Indian sub-continent. He was also a geologist and took an interest in archaeology.

His greatest contribution lies in the study of the botany of the plants. His researches are useful in continent division theory, in finding the age of south plateau, the growth of Himalayas after the formation of glosipatris vegetation and in studies of fossils in Botany.

On which research (investigation) Prof. Satyendra Nath Bose was honoured in the international world for the first time ? Describe briefly.

Prof. Satyendra Nath Bose sent his research paper relating to malt equation to a British research magazine ‘Philosophical Magazine’ for publishing in $$1923$$. But a referee rejected it. So, he sent a research paper relating to malt equation to world famous scientist Albert Einstein. Einstein translated the research paper into German language and got published in a magazine named Zeil for Physik. In this research, a new kind of statistics was formulated. Thus, he was honoured in the international world for the first time.

What were the main achievements of India in Science ?

The modern age is an era of science. The achievements of Science are possible due to the continuous efforts and research of scientists. Aryabhatta was the first scientist who told that the earth is spherical and it rotates on its axis, by which day and night formed. Brahmagupta was the first mathematician who gave the law of working of zero. Raman effect was given by Chandra Shekar Venkataraman. He passed the monochromatic light rays of mercury through some transparent substances and obtained spectrum on an ordinary spectrograph. He saw new lines in the spectrum and named them Raman lines. He declared Raman effect in a meeting of scientists on

1616 He was awarded Noble prize of Physics in 1930. Raman effect helped in understanding the molecular structure of a substance. Much research work was done on Raman effect after Laser rays.

What was the name of the apparatus constructed by Sir Jadish Chandra Bose ? What dis he show by this apparatus ?

He constructed an apparatus named Crescograph which could record the sensitivity of plants towards changes in light, temperature, etc. He tried to establish similarity of behaviour of plants like other living beings. He performed his experiment in the presence of scientists of the world on $$10$$th May $$1901$$. He also studied the sensitivity of plants for manures, wireless waves, and light. His apparatus was much praised in Paris Science Congress, in $$1907$$.

What are Wilson theorem and Pell's equation ?

Wilson theorem- It is propounded by Bhaskarachaiya-I.
According to Wilson’s theorem, any integer, $$ p > 1 $$ is a prime number, if and only if $$ (p -1)! = -1$$. He also derived the formula $$ 8X^2 + 1 = $$ is which is called as Pell's equation.

In which sphere did Meghnad Saha do research work ? Describe his Scientific achievements briefly.

Meghnad Saha did his research work in Astrophysics. He did thorough research on selective radiation pressure and its application to Astrophysics.

Scientific achievements: When Meghnad was only $$25$$ years old, he wrote several research papers related to the light of the sun and starts after performing experiments. He gave ionization formula. On the basis of which , astrologer studied the temperature of the sun and stars , the intensity of their light , their size etc. He established National Academy of Sciences for creating Scientists. He also organised Indian Institute of Nuclear Physics.

Write the biography of Varamihira and explain the scientific works of Varamihira in detail ?

Varahmihira was born in 499 A.D., in a family of Brahmins, settled at Kapittha, a village near Ujjain. His father, Adityadasa was a worshipper of the god Sun and it was he, who taught Varahamihira, astrology. On a visit to Kusumapura (Patna), young Varahamihira met the great astronomer and mathematician, Aryabhatta. The meeting inspired him so much, that he decided to take up astrology and astronomy as a lifetime pursuit. At that time, Ujjain was the centre of learning, where many schools of arts, science and culture were flourishing, in the prosperity of the Gupta reign. Varahamihira therefore, shifted to this city, where scholars from distant lands were gathering.

In due course, his astrological skills came to the notice of Vikramaditya Chandragupta II, who made him, one of the Nine Gems of his court. Varahamihira’s mathematical work included the discovery of the trigonometric formulas. He improved the accuracy of the sine tables of Aryabhata-I. He defined the algebraic properties of zero as well as that of negative numbers. Furthermore, he was among the first mathematicians, to discover a version of what is now known as Pascal’s triangle. He used it to calculate the binomial coefficients.

His treatise such as Pancha Siddhantika (Five Principles), Brihatsamhita (Master collection), Brahjataka (Astrological work) have put him on as high a pedestal in Astrology, as Kautilya’s in Political philosophy, Manu’s in Law or Panini’s in Grammar.

Varahamihira’s main work is the book Pancha Siddhantika (“Treatise on the five Astronomical Canon’s which gives information about old Indian texts, which are now lost). The work seems to be a treastise on mathematical astronomy and it summarises five earlier astronomical treatises, namely, the Surya Siddhanta.

Romaka Siddhanta, Paulisa Siddhanta, Vasishtha Siddhanta and Paitama Siddhanta. Panch Siddhanta holds a prominent place, in the realms of astronomy.

Varahamihira was learned in the Vedas, but he was not a blind believer in the supernatural. He was a scientist. Like Aryabhatta before him, he declared that the earth was spherical. In the history of science, he was the first to claim that some “Force” might be keeping bodies stuck to the round earth. The force is now called gravity.

Define Science. Write the main objectives of Science.

Word science is derived from the Latin word Scientia, which means to know. A systematic knowledge of nature verified by experiments is called Science.
Objectives of Science:
The main objectives of science are:

To understand the functional role of nature and explain it in a complete form.
To provide knowledge of the laws of nature after verifying them by experiments.
To control nature by the applications of results of experiments performed through keen observation.
To improve and make human life easier by the use of available natural resources and solving the problems.
To eradicate superstitions (false notions) prevailing in the society.

The first Indian Satellite was named on which scientist ?

Aryabhatta.

Describe the main achievements of Sir Chandra Shekhar Venkat Raman.

Scientific Achievements of Sir C.V. Raman are as follows:
1. Sir C.V. Raman performed experiments on the dispersion of light by passing sunlight through water and pieces of ice. He explained that the cause of the blue color of the sea was a dispersion of sunlight. He published a research paper on diffraction in $$1906$$ when he was a student of M.Sc.
2. He passed monochromatic rays of mercury arc through some transparent substances and obtained spectrum on an ordinary spectrograph. He saw new lines in the spectrum and named them Raman lines. He described ‘Raman’ effect in the meeting of scientists at Bangalore on March $$16 $$ th, $$1928$$. He was awarded the noble prize in $$1930$$.
3. Raman effect helped in understanding the molecular structure of a substance. Much research work was done on the Raman effect after the discovery of Laser rays.
4. He established Raman Research Institute in Bangalore and continued his research work there throughout his life.

Dr. Bhabha identified which type of particles in radiations from space?

Subatomic particle (Micro particles)

Write a short note on initial space missions of USSR.

USSR took the initiative and sent the first man-made satellite Sputnik – $$1$$ in October $$1957$$ into space. Sputnik -$$1$$ orbited around the earth while maintaining a distance between $$939-215\,km$$ from the earth. The radio transmitters on Sputnik -1 sent data about higher level of atmosphere, in the form of beeps. It was burnt into pieces while entering the earth. USSR went further ahead and took the lead in sending the first animal, first man (Yuri Gagarin), exhibiting first spacewalk, landing an unmanned spaceship on a celestial body, and installing the space station named Salute-$$1$$.

Scientist were apprehensive about what at the time of launch of Pioneer $$10$$ ?

It was feared that the advanced alien civilization may attack Pioneer 10 after considering it as an attack by human civilization. Scientists feared that Pioneer 10 may be taken as an attack from inhabitant of earth and advanced alien civilization may retaliate against it.

As per Charak what were the reasons for genetic defects in a child?

Some deficiency or defect in parents

What was our concept about extra-terrestrial life at the time of launch of Pioneer 10? What step was taken to save us from imaginary apprehensions?

By the time Pioneer $$10$$ was launched in $$1972$$ many scientists began to develop a strong belief about possibility of more advanced life on other celestial bodies. Some scientists were also apprehensive of possible attacks from alien civilizations. Pioneer was to go beyond our solar system after passing through near Jupiter. It was anticipated that pioneer may come in contact with any advanced civilization during its eventual voyage.

It was feared that the advanced civilization may attack Pioneer $$10$$ after considering it as an attack by human civilization. A plate was fixed on Pioneer $$10$$ to rule out this misconception. The plate showed figures of a man and a woman with friendly posture and a message in sign language to show the real intention of voyage of Pioneer $$10$$.

How do the scientists think about extra terrestrial life ? What are your thoughts on this topic ?

Latest scientific researches show that there are one billion earth-like world and many of them are rocky like earth. There are about $$100$$ billion galaxies in the known universe. The senior scientist from NASA, Allen Stephen says that we have solid proof to tell that we shall be able to find extra terrestrial life in the coming decade.

People from the scientific community also believe that the extra-terrestrial life is abundant in number. It keeps on coming continuously on earth in the form of microorganisms. Scientists also believe that the first life form was not created on earth rather came from somewhere else. Another group of scientists thinks that there is possibility of life outside the earth but that may not be as developed as on earth. They believe that only having a rocky planet with water is not enough to sustain life.

I think that alien life can be in different stages of development. At some planet, the alien life may be highly advanced. At others, it can be in the form of microorganisms only.

Match the column:

Bird Man of India	Dr. Salim All
Missile Man	Dr. A. P. J. Abdul Kalam
Father of Plastic Surgery	Sushruta
Father of Nuclear Science in India	Dr. Bhabha

Comment on Dr. Kalamt contribution in defence and space technology.

Dr. Kalam worked as a senior scientist of Defence Research and Development Organisation to work on hovercraft project. In $$1962$$ he was sent to Indian Space Research Organisation to work on various projects. He was given the charge of SLV project and SLV-3 was successfully launched after that. Eventually, he was given the charge of Integrated Guided Missile Development Programme (IGMDP) which enabled India to successfully test fire various missiles like Prithvi, Agni, Trishul, Nag and Akash. He also lead the tent explosion at Pokharan in $$1958$$.

What is the contribution of Dr. Panchanan Maheshwari in botany?

Dr. Panchanan Maheswhari specially worked on plant embryology. He developed a new branch by combining embryology viah plant physiology and with the new-found knowledge succeeded in growing different floral parts by artificial nutriton. He was so famous that not only Indians but students from America. Argentina and Australia used to come to do research work under his guidance. About 60 students completed their doctorate under his guidance.

Write about life and contributions of Dr. C. V Raman.

Chandrashekhar Venkat Raman was born on $$7^{th}$$ November $$1888$$ in Tamil Nadu. He cleared M. Sc. (Physics) in $$1907$$ at the age of $$19$$. He started his career as Deputy Accountant General under government of India. Raman left his job of accountant to devote time on science. After that he joined as a professor of physics at Calcutta University. During his tenure as professor. Raman discovered his famous *Raman Effect' in $$1929$$. For this discovery. he was awarded the Nobel Prize in $$1930$$. 'Raman Effect is also known as 'Raman Dispersbri. Raman explained the reason for blue colour of sea and sky. He also studied at lot about solid, liquid and gas. Additionally he conducted valuable research on magnetism, X-rays. structure of matter, colour and sound. He died on $$20^{th}$$ November $$1970$$.

Write about life and contributions of Sushruta.

Sushruta was born in $$600$$ BC. He got the basic training in medicines at ashram of Dhanwantari. Sushruta was the pioneer to give knowledge of surgery to the world. In his book Sushruta Samhita' he has elaborated about surgery in painstaking detail. Sushruta proposed about deficiency syndrome. He also practiced heating the surgical instruments before surgery in order to properly sterilize the instruments.

Many books mention plastic surgery of nose, ears and lips by Sushruta. In fact, he is also known as the father of plastic surgery. He has mentioned $$101$$ instruments for surgery. One of his tools was similar to spring forceps used by surgeons of the modern trne. He also came with elaborate instructions to maintain cleanliness and hygiene in hospital.

Explain the fundamental aspects of any science.

Any science has two aspects, viz. fundamental science and applied science. While fundamental science facilitates our understanding about various phenomena the applied science affects the human life and facilitates economic progress of the humankind.

As per Ayurveda, which are the three doshas which regulate the functioning of body?

Vata, Pitta and Kafa

Which incident motivated Dr. j Prafullachandra Ray to start a company? What happened after that?

After coming back to India, he joined the Presidency College as Assistant Professor. At the same time some people Qualification and lesser ability were working at higher posts and drawing higher salaries. When Dr. Prafullchandra complained about this to then Director of Education Department, the British director satirically told him, 9f you are such an able chemist then you should start Business.

He was so stirred by that satire that with a meager capital of Rs. $$800$$ he started the Bengal Chemical Pharmaceutical Works in $$1892$$ to produce allopathic medicines. Today, that company has progressed into a billion rupees company and has catalysed many industries in the country.

Which topic was of common interest for Charak and Mendel?

Inheritance

Write a short note on education of Dr. A P J Abdul Kalam.

Dr. Kalam got primary education at Rameshwaram. Then he moved to Schwartz Higher Secondary School in the neighbouring Ramanathpuram. to study science. After that, he studied Aeronautical Engineering at Madras University of Technology. He got entry in Madras University of Technology in $$1954$$ to study Aeronautical Engineering.

Write about life and contributions of Dr. A. P J. Abdul Kalam.

Dr. Abul Pakir Jainulabdin Abdul Kalam was bom on $$15^{th}$$ October $$1931$$. After obtaining his primary education at Rameshwararm, he moved to Schwartz Higher Secondary School in the neighbouring Ramanathpuram to sandy science. Then he studied Aeronautical Engineering at Madras University of Technology. Dr. Kalam worked as a senior scientist of Defence Research and Development Organisation to work cn hovercraft project. In $$1962$$, he was sent to Indian Space Research Organisation to work on various projects. He was given the charge of SW project and SW-3 was successfully launched after that. Eventually. he was given the charge of Integrated Guided Missile Development Programme (IGMDP) which enabled India to successfully test fire various missiles, like Prithvi, Agni, Trisha, Nag and Akash He also lead the test explosion at Pokharan in $$1958$$.

Make a short note on education of Dr. Bhabha.

After studying at Cathedral John Canon High School and Elphinstone College. Bhabha went to the Cartridge University for higher education. After graduating from Cambridge in $$1930$$, he began advanced study in theoretical physics. He conducted research in the field of cosmic ray and atomic energy.

Write about life and contributions of Dr. Salim Ali.

Dr. Salim Ali was born on $$12^{th}$$ November $$1896$$. Salim Ni got his initial education from St Xavers College. Bombay. He was a renowned ornithologist and naturalist. He is known as the 'Birdman' of India. Salim All was the first Indian to arrange for systematic survey of birds in India. His books on birds have helped immensely in enriching the knowledge about birds. He was conformed with the second highest civilian award of India, the Padma Vibhushan, in $$1976$$. After become chember of Bombay Natural History Society in $$1947$$, he utilized his influence to obtain government aid for this institution. He playact important role in formation of Bharatpur Bird Sanctuary (Keila Dee National Park). He also made great efforts to stop the construction of a dam project which was a threat to the Silent Valley National Park.

Name two Indian born physicists who have been awarded Nobel Prize in physics.

C.V.Raman and S.Chandra Shekhar.

Name any one fundamental force in nature.

Gravitational force.

Mention one of the major contributions of S. Chandrashekhar in the field of Physics.

Chandrashekhar's limit ($$1.44$$ solar mass).

What is the original name of the word Physics?

‘Fusis’ is the original name of the word Physics.

Which is the weakest force in nature?

Gravitational force.

Write an essay on the importance of Physics.

We are surrounded by physics all the time, and whether we realize it or not, we use physics everyday. Physics the study of matter and energy, is an ancient and broad field of science.

Though, there are many definitions of physics, yet it can be defined as, "The study of the properties of matter, energy and their mutual relationship.

Scope and Expansion of Physics

Physics is the branch of science, which deals with the properties of matter and energy and the relationship between them. The scope of physics is very wide and vast. It deals with not only the tinniest particle of atoms but it also dwells upon the natural phenomenon like galaxy, milky way, solar and lunar eclipse etc.

Branches of Physics

Physics is broadly classified into two parts.

(A) Classical physics

(B) Modern physics.

For information

1. Macroscopic physics: Under the macroscopic, physics comes the astronomical and earth related incidents. The principles of classical mechanics clearly define macroscopic physics.

2. Microscopic physics: Microscopic physics covers the molecular, atomic and nuclear incidents. Quantum mechanics is studied to understand the microscopic physics.

3. Mesoscopic physics: It is a subdiscipline of condensed matter physics that deals with materials of an intermediate length.

(A) Classical physics: Classical physics includes the traditional branches and topics that were recognized and fairly well developed before beginning of the 20th centaury. It is mainly concerned with the laws of motion and gravitation by Sir Isaac Newton and a kinetic theory and thermodynamic by James Clark Maxwell. Classical physics is mainly concerned with matter and energy. In this branch, energy and matter are considered as separate entities.

Classical mechanics, Optics, Acoustics and Electromagnetics are the traditional branches of classical physics.

(i) Mechanics: Mechanics is the study of physics of motion and how it relates to the applied forces.

(ii) Thermodynamics: Thermodynamics is the branch of physics, which deals with the study of heat and its relation with energy and work. Modes of transfer of heat, efficiency of heat engines and refrigerators are also included in thermodynamics.

(iii) Electromagnetism: Electromagnetism is a branch of physics involving the study of electricity, magnetic effect and electromagnetic waves.

(iv) Acoustics: We can define acoustics as a branch of physics, which studies how sound is produced, transmitted, received and controlled.

(v) Optics: Optics involves the study of various phenomena connected with light and optical instruments like microscope, telescope etc.

(B) Modern physics: Modern physics is the branch of physics, which is mainly concerned with the theory of relativity and quantum mechanics.

Albert Einstein and Max Plank were the pioneers of modern physics.

1. Relativity: Relativity is concerned with the study of those bodies that move with the speed almost same as the speed of light.

2. Quantum Mechanics: In quantum mechanics, we study the about modern principles of physics, dual nature of light and particles etc.

3. Atomic Physics: Atomic physics is the branch of physics which deals with the composition of atom apart from nucleus. It is mainly concerned with the arrangement and behaviour of electrons in shells around the nucleus.

4. Nuclear Physics: Nuclear physics is the branch of physics which deals with constituents, structure, behaviour and interaction of atomic nuclei. In the modern age, nuclear physics has got a very wide scope. It is used in power generation, nuclear weapons, medicines etc.

Apart from these branches, there are many branches of physics. Some of them are... Bio Physics, Electronics, Plasma-Physics, High Energy Physics, Astrophysics, Condensed Matter Physics, Solid State Physics, Environmental Physics, Computational Physics, Polymer Physics, Materials Physics and Cryogenics.

1753803_1832456_ans_d535ad83c1c44a30b1fffee0afa13243.png

Which is the strongest & weakest force in nature?

$$Strongest - strong nuclear force $$

$$Weakest - gravitational force. $$

Name four fundamental forces of nature out of the four, which one is
(a) strongest and
(b) weakest?

The forces are:

Gravitational force
Electromagnetic force
Strong nuclear force strongest
Weak nuclear force

(a) The nuclear force is the strongest.
(b) Gravitational force is weakest.

What is the advantage of ploughing the field?

By ploughing the soil, the small capillaries in the soil break down, hence the water does not evaporate through them. This keeps the field moisturised for a lone time which helps in germination of seeds.

State the 4 basic forces of nature.

1. Gravitational force
2. Elector magnetic force
3. Strong nuclear force
4. Weak nuclear force.

Conceptual Questions
Do some research to answer these questions: Who invented the metal detector? Why? What are it's limitations?

In 1881, an assassin shot President James Garfield. The bullet was lost in his body. Alexander Graham Bell invented the metal detector in an effort to save the President's life. The coil is preserved in the Smithsonian Institution. The detector was thrown off by metal springs in Garfield's mattress, a new invention itself. Surgeons went hunting for the bullet in the wrong place. Garfield died.

In this $$1798$$ experiment, Cavendish was said to have "weight the Earth". Explain this statement

Cavendish determined G, and we know that The Earth creates a gravitational field at its surface according to $$g=\dfrac{GM}{R^2}$$

The factors $$g$$ and $$R$$ are known, so as soon as Cavendish measured G, he could compute the mass of the Earth.

If the current position and velocity of every particle in the Universe were known, together with the laws describing the forces that particles exert on one another, the whole future of the Universe could be calculated. The future is determinate and preordained. Free will is an illusion. Do you agree with this thesis? Argue for or against it.

The current consensus is that the laws of physics are probabilistic in nature on the fundamental level. For example, the Uncertainty Principle states that the position and velocity (actually, momentum) of any particle cannot both be known exactly, so the resulting predictions cannot be exact. For another example, the moment of the decay of any given radioactive atomic nucleus cannot be predicted, only the average rate of decay of a large number of nuclei can be predicted in this sense, quantum mechanics implies that the future is indeterminate.

Write the biography of Aryabhatta and describe their main scientific works in detail ?

Aryabhatta: Aryabhatta was an acclaimed mathematician astronomer. He was born in Kusumapura (Patna) in Bihar, India. His contribution to mathematics, Science and astronomy is immense and yet he has not been accorded the recognition in the world history of science. At the age of 24, he wrote his famed “Aryabhatiya”. He was aware of the concept of zero, as well as the use of large numbers up to 1018. He was the first to calculate the value for ‘pi’ accurately, to the fourth decimal point. He devised the formula for calculating areas of triangles and circles. He calculated the circumference of the earth as 62832 miles, which is an excellent approximation, and suggested that the apparent rotation of the heavens was due to the axial rotation of the earth on its axis.

He was the first known astronomer to devise a continuous counting of solar days, designating each day with a number. He asserted that the planets shine, due to the reflection of sunlight, and that eclipses occur due to the shadows of the moon and earth. His observations account for the ‘flat earth concept and lay the foundation for the belief that earth and other planets orbit the Sun.

Scientific works and achievements:

Direct details of his work are known only from the Aryabhatiya, His disciple Bhaskara I, calls it Ashmakatantra (or the treatise from the Ashmaka). The Aryabhatiya is also occasionally referred to as Arya-shatas-ashta (literally, Aryabhata’s 108), because there are 108 verses in the text. It also has 13 introductory verses, and is divided into four or chapters.

Aryabhatiya’s first chapter, Gitikapada, with its large units of timc-Kalpa, manvantra, and Yuga-introduces a different cosmology. The duration of the planetary revolutions during a mahayuga is given as 4.32 million years.

Ganitapada, the second chapter of Aryabhatiya has 33 verses, covering mensuration, arithmetic and geometric progressions, gnomon or shadows, simple, quadratic, simultaneous, and indeterminate equations. Aiyabhatiya’s third chapter, Kalakriyapada explains different units of time, a method for determining the positions of planets for a given day, and a seven – day week with names for the days of week.

The last chapter of the Aryabhatiya, Golapada describes Geometric/ trigonometric aspects of the celestial sphere, features of the ecliptic, celestial equator, shape of the earth, cause of day and night and zodiacal signs on the horizon.

(i) It is speculated that Aryabhata used the word (approaching), to mean that not only is this an approximation but that the value is incommensurable or irrational.

(ii) In Ganitapada, he gives the area of a triangle as: “for a triangle, the result of a perpendicular with the half-side is the area. He discussed sine, by the name of ardha-jya or half-chord.

(iii) Like other ancient Indian mathematicians, he too was interested in finding integer solutions to Diophantine equations, with the form $$– ,+$$ by $$= ,c;$$ he called it the (meaning breaking into pieces) method.

(iv) His contribution to the study of Algebra is immense. In Aryabhatiya, Aryabhata provided elegant results for the summation of series of squares and cubes through well-tried formulae. (v) He correctly believed that the earth rotates about its axis daily.

(vi) In Aryabhatiya, he writes that ‘setting and rising of planets’ is a perception, similar to that of Someone in a boat going forward sees an object going backwards.

(vii) He correctly, asserted that the planets shine, due to the reflection of sunlight, and that the eclipses occur due to the shadows of moon and earth, and not caused by a demon called ‘Rahu’.

(viii) He correctly deduced that the orbits of the planets are ellipses.

Other Achievements:

The gave the knowledge of Algebra, Intermediate equations, Trigonometry, Place value system and zero and also the motions of the Solar system.

Write the biography of Bhaskaracharya ? and describe their main scientific works in detail?

Bhaskara was born in 1114, near Vijjadavida (believed to Bijjaragi of Vijayapur in modern Karnataka).

Bhaskara II, also known as Bhaskara or as Bhaskaracharya, was a 12th-century Indian mathematician. He was also a renowned astronomer, who accurately defined many astronomical quantities, including the length of the sidereal year. A brilliant mathematician, he made the significant discovery of the principles of differential calculus and its application to astronomical problems and computations centuries before European mathematicians, like Newton and Leibniz made similar discoveries.

It is believed that Bhaskara II was the first to conceive the differential coefficient and differential calculus. Bhaskara II wrote the first work with full and systematic use of the decimal number system and also wrote extensively on other mathematical techniques and on his astronomical observations of planetary positions, conjunctions, eclipses, cosmography, and geography. In addition, he also filled many of the gaps, in his predecessor, Brahmagupta’s work. In recognition of his invaluable contributions, to mathematics and astronomy, he has been called the greatest mathematician of medieval India.

Scientific work and achievements:

1. He made many significant contributions to mathematics, throughout his career. He is credited to have given a proof of the Pythagorean theorem, by calculating the same area in two different ways, and then cancelling out terms, to get $$a_2 + b_2 = c_2.$$

2. His work on calculus was groundbreaking and much ahead of his times. He not only discovered the principles of differential calculus and its application to astronomical problems and computations but also determined solutions of linear and quadratic indeterminate equations (Kuttaka). The works in calculus performed by the European mathematicians of the 17th century is comparable to the rules he had discovered, way back in the 12th century.

3. His major work ‘Siddhanta Siromani’(“Crown of treatises”) was completed in 1150 when he was 36 years old. Composed in the Sanskrit Language, the treatise consists of 1450 verses. The work is divided into four parts called “Lilavati, “Bijaganita’, and ‘Goladhyaya’, which are also sometimes considered four independent works. The different sections deal with different mathematical and astronomical fields.

4. The first part “Lilavati’ consists of 13 chapters, mainly definitions, arithmetical terms, interest computation, arithmetical and geometrical progressions, plane geometry and solid geometry and many others aspects of mathematics. It also has a number of methods for computing numbers, such as multiplication, squares, and progression.

5. His work “Bijaganita’(“Algebra”) was a work in 12 chapters. This book covered topics like positive and negative numbers, zero, surds, determining unknown quantities, and elaborated the method of ‘Kuttaka’for solving indeterminate equations and Diophantine equations. He also filled many of the gaps in his predecessor, Brahmagupta’s work.

6. The sections ‘Ganitadhyaya’ and ‘Goladhyaya’ of ‘Siddhanta Shiromani ’ are devoted to astronomy. He used an astronomical model developed by Brahmagupta, to accurately define many astronomical quantities, including the length of the sidereal year. These sections covered topics such as mean longitudes of the planets, true longitudes of the planets, solar and lunar eclipses, cosmography, geography etc.

7. Bhaskara II was especially known for his in-depth knowledge of trigonometry Discoveries first found in his works, including computation of sine of angles of 18 and 36 degrees. He is credited to have discovered spherical trigonometry, a branch of spherical geometry, which is of great importance for calculations, in astronomy, geodesy and navigation.

8. Bhaskara-II major work was the treatise-‘Siddhanta Siromani’, which was further divided into four parts, each of them dealing with diverse topics on arithmetic, algebra, calculus, trigonometry, and astronomy. He is considered to be a pioneer in the field of calculus, as it is probable that he was the first to conceive the differential coefficient and differential calculus.

S.No	Scientists	Inventions
1	Michael Faraday	First battery
2.	George Simon Ohm	Radioactivity
3.	Volta	Dynamo
4.	Henry Becquerel	Ohm's law

Physical World - Class 11 Engineering Physics - Extra Questions