NCERT Solutions for Class 11 Physics Chapter 1 Physical World

This is the best resource of NCERT Physics Solution for Class 11 Chapter 1 Physical World. Students can find familiar solutions with the exam format and syllabus. The most recent revision of the CBSE Syllabus for 2022-23 specifies that Physics includes ideas and problems. Students are strongly advised to use the NCERT Solutions when responding to the textbook questions to perform well on the exam.

Question 1.1:

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"?

Answer:

The physical universe as a whole is extremely complicated. The biological world is complex in its own right. Furthermore, space, time, and mass scales are substantially different orders of magnitude. Despite this, a very small number of fundamental laws can be used to describe practically all physical occurrences. In this light, Einstein's statement is very understandable.

Question 1.2:

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

Answer:

Light travels in a straight line, a familiar observation in daily life. Huygens' wave idea went against conventional wisdom when he first proposed it. But as soon as wave theory was successfully used to explain reflection, refraction, and other phenomena, it quickly became dogma. We concluded that light had dual characteristics when the photoelectric effect was discovered, and it was revealed that the wave theory of light could not explain the phenomenon. It might act both like a wave and a particle. We could think of more comparable instances in the history of science.

Question 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.

Answer:

Science is a systematic investigation of observations. Patiently analysing these observations, a scientist derives some laws. For instance, Tycho Brahe observed the planets' motions for twenty years. Kepler's three renowned laws of planetary motion were developed from this vast collection of observations. Politics is the art of the conceivable, just as science is the art of the solvable.

Question 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.

Answer:

The following list includes some significant factors that have constrained India's progress in science:

1. Lack of facilities and resources for high-quality scientific research.
2. Science instruction needs to be appropriately focused and oriented. Depending on what we need, it needs various instructions.
3. Poor pay scales and other amenities for scientists compared to administrators. Indian society is full of superstitions and is highly traditional. Nearly no science education is provided in rural areas, depriving most of the population of the advantages of advances in science and technology. As a result, they take a while to absorb new scientific tendencies.
4. Between researchers and industrialists, there is no coordination. The real users of cutting-edge science and technology are the industrialists. The country's businesses have little faith in the scientific prowess of India.

Question 1.5:

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?

Answer:

Numerous phenomena that depend on the presence of electrons have been predicted and confirmed in daily life. Nothing can be explained by the idea that ghosts exist even though they cannot be seen. Therefore, it is clear that there is no justification for comparing the two circumstances.

Question 1.6:

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?

1. 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.
2. 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 thecrab 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 is 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].

Answer:

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

Question 1.7:

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?

Answer:

The development of contemporary science and the industrial revolution are intimately related. Another significant contribution that research made to the growth of contemporary science was the public attention and support it received when it was used to address industrial concerns.

Here are some of the major discoveries and their applications:

1. One of the major advancements in science and technology during the industrial revolution was the steam engine, which was created by applying thermodynamics and heat.
2. The application and discovery of electricity aided the invention of motors and dynamos. Similar to how the study of gravity sparked interest in motion, which in turn sparked the creation of cannons and other weapons. Western nations governed the rest of the globe thanks to this technology, which gave them power.
3. Exploration for minerals and the army both benefited from the discovery of explosives.

These are just a few technological advancements that have contributed to England and Europe's eminent global positions.

Question 1.8:

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.

Answer:

A new industrial revolution is currently occurring and is projected to occur soon thanks to some important modern areas of technology and science, including:

1. Artificial Intelligence
2. Super-fast computer.
3. Biotechnology
4. Development of superconducting materials at room temperature.
5. Electronics, information technology, nanotechnology, and space sciences developments are among the fields where there have been advancements.

Question 1.9:

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

Answer:

Humans will be able to build wormholes in the year 2220, enabling travel to far-off cosmological locations. We have built human communities outside the planet and will come into contact with extraterrestrial life. We will be able to understand the true nature of our universe and existence to a greater extent as quantum physics advances. Our technology's pollution won't harm the earth. Humans and artificial intelligence might conflict occasionally.

Question 1.10:

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 human society. How, if at all, will you resolve your dilemma?

Answer:

A science expert seeks the truth. Every new scientific finding discloses a fundamental reality about the universe. Any discovery, whether harmful or beneficial to humanity, must be made public.

But given that, we cannot afford to ignore the implications. Before revealing it, we must first determine how beneficial or bad repercussions it will have. Suppose we know that a certain discovery will only harm the general public. In that case, it is advisable to keep it a secret from everyone else to save the researchers and scientists working on it. In this manner, the discovery can benefit cultures in the long run without totally ruining them at the time.

Question 1.11:

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:

1. Mass vaccination against smallpox to curb and finally eradicate this disease from the population. (This has already been successfully done in India).
2. Television for the eradication of illiteracy and for mass communication of news and ideas.
3. Prenatal sex determination
4. Computers for the increase in work efficiency
5. Putting artificial satellites into orbits around the Earth
6. Development of nuclear weapons
7. Development of new and powerful techniques of chemical and biological warfare).
8. Purification of water for drinking
9. Plastic surgery
10. Cloning

Answer:

1. Good. The feared illnesses were wiped out on Earth with the aid of widespread immunisation.
2. Good. Television is a powerful tool for mass communication and entertainment that also aids in the literacy drive.
3. Bad. Prenatal sex determination is viewed negatively since it leads to the practise of abortion when a foetus is a female.
4. Good. The use of computers improves productivity.
5. Good. Artificial satellites aid in international communication.
6. Bad. If nuclear weapons are utilised improperly, mankind might be utterly destroyed.
7. Bad. These methods might be abused for negative ends.
8. Good. People's health is improved by purified water.
9. Neither excellent nor impure. Plastic surgery serves to remove a certain sort of deformations in those in need, hence it cannot be classed as either good or negative.
10. Bad. Cloning has the ability to disrupt human society's traditional family structure.

Question 1.12:

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 obscurantist 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?

Answer:

Mass media, such as the internet, newspapers, television, and radio, should be used to spread awareness of scientific explanations for commonplace events. It is important to spread scientific knowledge to the general public so that they might understand the true origins of phenomena and lose their superstitious convictions.

Question 1.13:

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.

Answer:

There are no noticeable differences between men and women regarding labour, intelligence, and decision-making. The physique and feelings of men and women are mostly determined by nature. The nutritional value of a prenatal and postnatal diet greatly aids the human body's growth. The female mind and physique will be just as effective as a man's if equal chances are granted to both genders. A long list of outstanding women who have succeeded in their different disciplines can be found. Names of:

→Madame Curie

→Indira Gandhi

→Florence Nightingale

→Margaret Thatcher

→Mother Teresa

→Sarojini Naidu

→Kalpana Chawla

have been taken from various disciplines, including science and sociology, and they are all well-known for their contributions to humankind. Women are just as important to society as males are, given their contributions to every aspect of life in the nation.

Question 1.14:

"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.

Answer:

Dirac's hypothesis is accurate. Equations that encompass complete theories and stand up to experimental findings are inherently easy to understand, compact, and symmetrical, which makes them genuinely lovely. E = mc², E = hv, F = mg, and P.E = mgh are a few illustrations of lovely equations.