Learning Ashram

Physics Class 11 - Chapter 1

Q 1.1Some 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”?

Ans:The whole of the physical world around us is very complex in nature because of the occurrence of millions of phenomena. The biological world has its own complexities. So the world seems incomprehensible i e. as if it cannot be understood. Moreover, we come across wide ranges of mass, length and time which surprisingly be understood and expressed in terms of few basic laws. In other words, the complex nature of the physical world from atomic to astronomical ranges can be understood in terms of a few basic concepts, so the physical world becomes comprehensible. When viewed in this context, Einstein's admiration becomes very clear.

Q 1.2 “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.

Ans:Dogma.is an established opinion which is questioned by only a few. But heresy is anything against the established belief and theory which causes a few ripples in Ihe mind of the intelligent. For

example (i) Thomas Young's wave theory of light started as a heresy and finally ended as 'dogma' when Einstein and other replaced it by quantum theory of light.

(ii) In ancient times, Ptolemy postulated that earth is stationary and all the heavenly bodies like sun, stars, planets etc. revolve around it. Later, an Italian scientist Galileo postulated that sun is stationary and earth along with other planets is revolving around the sun. Galileo was punished by the then authorities for spreading wrong concepts. But later on Newton and Kepler supported Galileo's theory and now it is a dogma.

(iii) There was an heresy that inertia of a body depends upon its energy. Einstein put forth a single equation relating mass and energy which is called as mass-energy equivalence relation (E = rnc2) and this is a dogma in Physics.

Q 1.3 “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.

Ans: It is a well known fact that to win over votes, politicians make anything and everything possible even when They are least sure of the same. Science is a systematised study of observations. A scientist patiently analyses these observations and comes out with certain laws. e.g. Tycho Brahe worked for twenty long years to make observations on planetary motions. J. Kepler formulated his three famous laws of planetary motion from this huge reservoir of observations. Thus the statement that science is the art of the soluble means that a wide variety of physical processes are understood in terms of only a few basic concepts i.e. 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.

Q 1.4 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.

Ans: Following are some of the important factors which have hindered India's march towards becoming a world leader in science and technology.

(i) One of the main factors is that the young scientists and technologists are denied the academic freedom which is so very necessary for making advances in science and

(ii) The management of science education in our country is bureaucratic.

(iii) There is practically no co-ordination between the researchers and the industrialists who are the actual consumers of new research and technology. Indian industrialists have little confidence in the ability of Indian scientists and they prefer to import technology from advanced countries.

(iv) The infrastructure for science education in schools and colleges in India is highly in poor state.

(v) Science education is neither properly oriented nor directed. It needs specific direction depending on our requirements.

(vi) Sufficient funds are not available for science and technology.

(vii) There is a lack of employment opportunities for science educated students in our country, thus it takes them away from science and technology.

(viii) 'Brain drain is another important factor that has hindered India's progress in science and technology. It leads to a large scale migration of scientists and technologists.

Q1.5No 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 ?

Ans :The existence of an electron is a fact because many phenomens have been actually observed in our daily life which depend upon the existence of electron. On the other hand, there is no phenomenon which can be explained on the basis of the existence of ghosts. Hence clearly, the comparison between the two cases is meaningless:

Q1.6The 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

[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].


Q1.7 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 ?

Ans: The following are the key scientific and technological outstanding contributions that triggered industrial revolution in England and Western Europe during that period :
(i) Steam engine formed on the application of heat and thermodynamics.
(ii) Blast furnace which converts low grade iron into steel.
(iii) Cotton gin which separates the seeds from cotton three hundred times faster than by the hand.
(iv) Discovery of electricity helped in designing dynamos and ' motors. .
(v) Discovery of explosives not only helped army but also mineral exploration.
(vi) Study of motion and making guns/canons was led by the study of gravitation

Q1.8 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.

Ans: The following are the key areas which will transform
radically the present society :
(i) Development of super conducting materials at room
(ii) Development of infrared detectors used in night vision, medical surveyallence, remote sensing, geological survey
(iii) Agriculture is the fundamental area which will transform the village life all over the world.
(iv) There is a magic revolution in the field of information technology which includes internet, electronic media, superfast computers, satellite communications.
(v) Progress in biotechnology and genetic engineering which may totally change the face of the world in coming years.

Q1.9 Write in about 1000 words a fiction piece based on your speculation on the science and technology of the twenty-second century.

Ans: Let us imagine a space ship moving towards a distant star, 500 light years away. Let it be propelled by current fed into the electric motor consisting of superconducting wires. In space, suppose there is a particular region which has such a high temperature that destroys the superconducting property of 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 it (i.e. 1st ship) continues its onward journey.

Physics Class 11 - Chapter 1