Andhra Pradesh BIEAP AP Inter 1st Year Physics Study Material 1st Lesson Physical World Textbook Questions and Answers.
AP Inter 1st Year Physics Study Material 1st Lesson Physical World
Very Short Answer Questions
What is Physics ?
Physics is a branch of science which deals with the study of nature and natural phenomena.
What is the discovery of C.V.Raman ? [T.S. Mar. 17, 16; Mar. 14]
In elastic scattering of light by molecules.
What are the fundamental forces in nature ?
- Gravitational force
- Electromagnetic force
- strong nuclear force
- weak nuclear force
Which of the following has symmetry ?
(a) Acceleration due to gravity
(b) Law of gravitation.
Law of gravitation. For example, the acceleration due to gravity at the moon is one-sixth that at the earth, but the law of gravitation is same both on the moon and the earth.
What is the contribution of S. Chandra Sekhar to physics ? [AP – Mar. ’17, ’16, ’15; TS – Mar. – ’15]
While studying the constitution of the stars, he has proved that the maximum mass that a white dwarf can have is 1.4 times the solar mass. This mass is known as Chandrasekhar limit. If a star crosses this limit, it has to face a catostropic collapse.
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 Einstein meant when he said : “The most incomprehensible thing about the world is that it is comprehensible” ?
The physical world when seen by a layman, presents us with such a wide diversity of things. It seems incomprehensible, ie as if it can not be understood. On study and analysis, the scientists find that the physical phenomena from atomic to astronomical ranges can be understood interms of only a few basic concepts i.e., the physical world becomes comprehensible. This is what is meant by Einsteins statement mode above.
“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.
The statement is true. For example, in ancient times, ptolemy postulated that earth is stationary and all heavy bodies like sum, stars, planets etc revolve around the earth, Later an Italian Scientist Galileo was postulated that sun is stationary and earth along with other planets is revolving around the sun. Galileo was punished by the authorities for spreading wrong concepts. How ever later on newton and kepler supported Galileo’s theory and now it is no more than a dogma.
“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.
It is well known that to win over vots, politicians would make anything and everything possible even when they are least sure of the same. The statement that science is the art of the soluble implies that a wide variety of physical phenomena are understood in terons of only a few basic concepts ie there appears to be unity in diversity as if widely different phenomena are soluble and can be explained in terms of only a few fundamental laws.
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.
In my view some important factors which have hindered the advancement of science in india are
- Lack of education.
- Poverty, which leads to lack of resources and lack of infrastructure.
- Pressure of increasing population.
- lack of scientific planning.
- Lack of development of work culture and self discipline.
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 every seen an electron. This is true. But there is so much of Evidence that establishes the existance of electrons, on the contrary, there is hardly any evidence, direct (or) indirect to establish the existance of ghosts’.
The shells of crabs found around a particular coastal location in Japan seem mostly to resemble that legendary face of 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.
[Note : This interesting illustration taken from Carl Sagan’s The Cosmos’ highlights the fact that often strange and inexplicable facts which on the first sight appear ‘supernatural’ actually turn out to have simple scientific explanations. Try to think out other examples of this kind).
Explanation (b) is a scientific explanation of the observed fact.
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 ?
Industrial revolution in England and western Europe in 1750 A.D. was triggered by some key scientific and technological advances. Development of steam engine, blast furnace and cotton gin and power loom are some of the examples.
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 fo this revolution.
Some of the key contemparary areas of science and technology which may transform the society radically are
- Development of superconducting materials at room temperature –
- Development of superfast computers
- Information explosion and advances in information technology
- Developments in biotechnology
- Developments of robots.
Write in about 1000 words is fiction piece on the science and technology of the twenty second century.
Imagine a space ship heading towards a star about 100.light years away. It is propelled by electric current generated by electromagnetic induction, as the space ship crosses the magnetic fields in space the current is given to an electric motor made of super conducting wires. Thus no energy would be required to propagate the space ship over it extire journey.
In a particular region of the space, suppose the temperature becomes so high that the super conducting property of the wires of the motor is destroyed. This causes a panic in the space ship because no power is generated by the motor.
In a split second, another space ship filled with matter and antimatter stored in different compartments to produce energy for the first ship comes to its rescue. And the first ship continues its onward 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, it at all, will you resolve your dilemma ?
Science is search for truth. If a discovery is of great academic interest, but is sure to have dangerous consequences for the human society, it must be made public. To reveal the truth and the means to prevent its misuse, both are the responsibilities of the scientist. For example, discovery of nuclear fission led to generation of electric power, and also to the development of an atom bomb, a weapon of mass destruction . The humanity at large has to be educated to use nuclear energy for peaceful purposes.
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
a) Mass Vaccination is good
b) Television for eradication of illeteracy and for mass communication of news and ideas is really good.
c) Prenatal sex determination is not bad, but people are misusing it. they must be educated to avoid its misuse in creating inbalance between the male arid female population.
d) computers for increase in work efficiency are good.
e) Putting artificial satellites in to orbits around the earth is a good development.
f) Development of nuclear weapons is bad as they are the weapons of mass destruction.
g) Development of new and powerful techniques of chemical and biological warfare is real bad as these weapons are destruction of mankind.
h) purification of water for drinking is good.
i) Plastic surgery is good.
j) Cloning is also good.
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 ?
Educating the common man is the only way to get rid of superstitious and obscurantistic attitudes. The mass media like news papers, magazines, radio, T.V. etc can play vital role school and colleges curricula can be suitably developed and teachers can take this responsibility.
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.
Given equal opportunity, women are at par with men. Development of human mind depends basically on nutrition content of prenatal and postnatal diet, and also on the care and use of the mind. There is no gender bias involved. Anything which can be achieved by man’s mind can also be achieved by women’s mind. Madam curie won Nobel Prize in physics. Mother teresa proved herself a saint. In politics Mrs. Indira Gandhi, Mr. Margarettheatcher, Mr’s. Bhandarnaike excelled others.
“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 equations and results in this book which strike you as beautiful.
The statement of great British physicist P.A.M. Dirac is partially true. For example f = ma; E = mc2 are some of simple and beautiful equations of physics which have universal application.
However, there is not the case always. The equations involved in general theory of relativity, some of the least works of higher physics are neither simple nor beautiful, they are rather difficult to understand.
Thought 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 th§ Bibliography at the end of this book.) Their writings are truly inspiring !
General books on physics make an interesting reading, students are advised to consult a good library. Surely you are Joking Mr. Feynman by Feynman is one of the books that would amuse the students. Some other interesting books are : physics for the inquiring mind by E.M, Rogers; physics. Foundations and frontiers by G. Gamow; thirty years that shook physics by G. Gamow; physics can be fun by perelman.
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 any other 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.
True, scientists like any other group of humans have their share of humorists ; lively, jovial, fun loving, adventurist people, some of them are absent minded introvert too. Students are advised to go through books by two great physicists, Feynman and Gamow to realise this view.