1. Why do we express laws of physics in mathematical form?
2. Name two advancements made in technology on the basis of physics.
3. Max Plank said, “We have no right to assume that any physical laws exist, or if
they have existed up to now, that they will continue to exist in a similar manner in
the future”. Comment.
4. In the words of Bertrand Russel, “We know very little, and yet it is astonishing
that we know so much, and still more astonishing that so little knowledge can
give us so much power”. Justify the statement.
5. How the fate of society is linked with the development of physics?
6. How do we classify elementary particles as baryons, mesons, and leptons?
Amongst which of these particles is the strong nuclear force dominant and
amongst which is the weak nuclear force dominant?
7. Which symmetry laws lead to (i) Law of conservation of energy and (ii) Law of
conservation of angular momentum?
8. Explain how does the elastic force in a spring arises.
9. Taking a suitable example from daily life, show that electromagnetic force is
enormously stronger than the gravitational force.
10.Mention four important discoveries of physics which have revolutioned modern
chemistry.
Answers
Explanation:
1 The role of mathematics in this scheme is to represent the laws of motion by equations, and to obtain solutions of the equations referring to observed conditions. The dominating idea in this application of mathematics to physics is that the equations representing the laws of motion should be of a simple form
2 Two advancements in technology on the basis of Physics are: (i) The study of satellites has made it possible to forecast the weather. (ii) The study of electro-magnetic induction has led to design the electric generators and motors.
3 We have no right to assume that any physical laws exist, or if they have existed up until now, that they will continue to exist in a similar manner in the future.
4 Until and unless we assume ourselves that our knowledge is limited and world is full of knowledge to be explored, we won't be able to increase our knowledge.e
If we consider ourselves so knowledgeable then there won't be any desire to explore anything new.
5 The fate of a society is closely linked to physics. Whatever is discovered in physics, it immediately affects the society. For example, 1. The developments of telephone, telegraph, telex enable us to quickly exchange messages between far off places
6 They are divided into baryons and mesons. The baryons are a class of fermions, including the proton and neutron, and other particles which in a decay always produce another baryon, and ultimately a proton. The mesons, are bosons.
7 That symmetry with respect to time shift gives rise to the law of conservation of energy, maybe the most important conservation law in physics. In a sense, time-shift symmetry is already built-in into the Schrödinger equation. The equation does not depend on what time you take to be zero.
8 When a spring is elongated, it exerts a force of elasticity which arises due to the net attraction between the neighbouring atoms of the spring. This net attraction is the sum of the electrostatic forces between the electrons and nuclei of these atoms.
9 A small object hanging on a string remains as it is despite a large attractive force of gravity due to the earth is a good example to show that the electromagnetic force is much stronger than the gravitational force.
10 (i) Study of radioactivity (ii) Study of isotopes by mass spectrographs (iii) X-ray diffraction etc.