# Physical World

## Class 11 NCERT Physics

### NCERT

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”?

##### Solution :

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.

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.

##### Solution :

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 , energy depends on the speed of the body.

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.

##### Solution :

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'.

4   Though India now has a large base in science and technology, which is fast expanding, it is still a long way from realizing 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.

##### Solution :

Some important factors in our view which have hindered the advancement of science in India are:$\\$ $\bullet$ Proper funds are not arranged for the development of research work and laboratories.$\\$ The labs and scientific instruments are very old and outdated.$\\$ $\bullet$ Most of the people in India are uneducated and highly traditional. They don't understand the importance of Science.$\\$ $\bullet$ There is no proper employment opportunity for the science educated person in India.$\\$ $\bullet$ There are no proper facilities for science education in schools and colleges in India.

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?

##### Solution :

No physicist has ever seen an atom but there are practical evidences which prove the presence of electron. Their size is so small, even powerful microscopes find it difficult to measure their sizes. But still its effects could be tested$\\$ On the other end there is no phenomena which can be explained on the basis of existence of ghosts.$\\$ Our senses of sight and hearing are very limited to observe the existence of both. So there is no comparison between the two given cases.