Physics Test Questions and Answers

Physics Test Questions and Answers 

�The word science originates from the latinverb sciential meaning ‘to know’

�The Sanskrit word ‘vijnana’ and the arabicword ‘Ilm’ convey similar meaning,namely ‘knowledge’

�Science is a systematic attempt to under-stand natural phenomena in as much detailand depth as possible, and use theknowledge so gained to predict, modifyand control phenomena.

�Science is exploring, experimenting andpredicting from what we see around us.

�The curiosity to learn about the world,unravelling the secrets of nature is the first step towards the discovery of science.

�The interplay of theory and observation or experiment is basic to the progress of science.

�Science is ever dynamic. There is no finaltheory in science and no unquestioned authority among scientists.

�Johannes kepler examined the extensive data on planetary motion collected by Tycho Brahe, the planetary circular orbitsin helio centric theory (sun at the centre ofthe solar system) imagined by Nicolauscopernicus had to be replaced by elliptical orbits to fit the data better.

�In 1911 by Ernest Rutherford established thenuclear model of the atom, which thenbecame the basis of the quantum theory of hydrogen atom given in 1913 by Niels Bohr.

�The concept of antiparticle was firstintroduced theoretically by Paul  Dirac in1930 and confirmed two years later by theexperimental discovery of positron (antiparticle) by Carl Anderson.

�The word physics comes from a Greek word meaning ‘nature’

�Here we remark on two principal thrusts in physics: Unification and reduction.

�Reductionism is at the heart of physics

Scope and Excitement of physics
�Basically,  there are two domains of interest:macroscopic and microscopic.

�The macroscopic domain includes phenomena at the laboratory, terrestrial and astronomical scales.

�The microscopic domain includes atomic,molecular and nuclear phenomena.

Note: Recently, the domain intermediate between the macroscopic and the microscopic (the so-called  microscopic physics) dealing with a few tens or hundreds of atoms, has emerged as an exciting field of research.

�Classical physics deals mainly with macroscopic phenomena and includes subjects like Mechanics, electrodynamics, Optics and Thermodynamics.

The propagation of radio waves in the ionosphere
�Thermodynamics, in contrast to mechanics, does not deal with the motion of the bodies as a whole. Rather, it deals with systems in macroscopic equilibrium and is concerned with changes in internal energy,temperature, entropy etc... of the system through external work and transfer of heat.

�The efficiency of heat engines and refrigerators, the direction of a physical or chemical process etc.. are problems of interest in thermodynamics.

Physics, Technology and Society
�As late as 1933, the great physicist Ernest Rutherford had dismissed the possibility of tapping energy from atoms.  But only a few years later, in 1938 Hahn and Meitner discovered the phenomenon of neutron-induced fission of Uranium, which would serve as the basis of nuclear power reactors and nuclear weapons.

�Physics giving rise to technology is the silicon ‘chip’ That triggered the computer revolution.

Some Physicist and their major contributions/discovery ::

1.Archimedes (Greece)-  principle of buoyancy, principle of the lever

2.Galileo Galilei (Italy)- Law of inertia

3.Enrico Fermi (Italy)- Controlled nuclear Fission

4.Christian Huygens (Holland)- Wave theory of light

5.Isaac Newton (UK)- Universal law of gravitation, Laws of motion, Reflecting telescope

6.Michael Faraday (UK)- Laws of electromagnetic induction

7.James clerk Maxwell (UK)- Electro magnetic theory, height an electromagnetic wave

8.JJ Thomson (UK)- Electron

9.Paul Dirac (UK)- Relativistic theory of electron, Quantum statistics

10.James chadwick (UK)- Neutron

11.Heinrich Rudolf Hertz (Germany)- Generation of electromagnetic waves

12.WK Roentgen (Germany)- X-rays

13. Albert Einstein (Germany)- Explanation of photo electric effect, Theory of relativity

14. Werner Heisenberg (Germany)- Quantum mechanics, Uncertainty principle

15.JC Bose (India)- Ultra short radio waves

16.CV Raman (India)- Inelastic scattering of light by molecules

17.MN Saha (India)- Thermal ionisation

18.SN Bose (India)- Quantum statistics

19.Homi Jehangir Bhabha (India)- Cascade process of cosmic radiation

20. S. Chandra Shekar (India)- Chandrasekhar limit, structure and evolution of stars

21. Marie sklodowska curie (Poland)- Discovery of radium and polonium, studies on natural radioactivity

22.Victor Francis Hess (Austria)- Cosmic radiation

23.Wolfgang Pauli (Austria)- Exclusion principle

24.RA Millikan (USA)- Measurement of electronic charge

25.Edwin Hubble (USA)- Expanding universe

26.Ernest Orlando Lawrence (USA)- Cyclotron

27.John Bardeen (USA)- Transistors, Theory of super conductivity

28.CH Townes (USA)- Maser, Laser

29.Ernest Rutherford (USA)- Nuclear model of atom

30.Niels Bohr (Denmark)- Quantum model of hydrogen atom

31.Louis Victor De Broglie (France)- Wave nature of matter

32.Hideki Yukawa (Japan)- Theory of nuclear forces

33.Lev Davidovich Landau (Russia)-  Theory of condensed matter, Liquid helium

34.Abdus Salam (Pakistan)- Unification ofweak and electromagnetic interactions

Fundamental Forces in Nature
�The correct notion of force was arrived at by Isaac Newton in his famous laws of motion.

�Fundamental forces in the nature are mainly classified into four types.. they are

Gravitational Force
�It is a universal force

�It is the weakest force among the all the basic forces in the nature.

Electromagnetic Force
�Electromagnetic force is the force between the charged particles.

�In between the unlike charges attraction forces are acting and in between the like charges repulsion forces are acting.

�It underlies the macroscopic forces like tension,friction, normal force, spring force, etc..

�Gravity is always attractive, while electromagnetic force can be attractive or repulsive.

�Another way of putting it is that masscomes only in one variety (There is nonegative mass), but charge comes in twovarieties; positive and negative.

Strong Nuclear Force

�The strong nuclear force is the strongest of all fundamental forces.

�It is charge-independent and acts equally between a proton and a proton, a neutron and a neutron and a proton and a neutron.

�It’s range is, however, extremely small of about nuclear dimensions (10-15m)

�It is the responsible for the stability of nuclei.

�Protons and neutrons are built out of still more elementary constituents called ‘Quarks’

Weak Nuclear Force
�In B-decay, the nucleus emits an electronand an uncharged particle called ‘neutrino’

Towards unification of forces
�Maxwell unified electromagnetism andoptics with the discovery that light is anelectromagnetic wave.

�Einstein attempted to unify gravity andelectromagnetism but could not succeed inthis venture.

Progress in unification of different forces/domains in nature :: 
1.Isaac Newton (1687)- Unifiedcelestial and terrestrial mechanics, showed that the same laws of motionand the law of gravitation apply tobothe the domains.

2.Hans christian oersted (1820),Michael faraday- Showed that electric and magnetic phenomena areinseparable aspects of a unifieddomain, electromagnetism

3.James clerk maxwell (1873)- Unifiedelectricity, magnetism and optics ,showed that light is anelectromagnetic wave

4.Sheldon Glashwo, Abdus salam,Steven Weinberg (1979)- Showed that the weak nuclear force could beviewed as different aspects of asingle electro-weak force.

5.Carlo Rubia, Simon Vander Meer(1984)- Verified experimentally the predictions of the theory of electro-week force.

Nature of physical laws :: Link between Technology and Physics

�Steam Engine: Laws of thermodynamics

�Nuclear Reactor: Controlled nuclear fission

�Radio and Television: Generation, Propagation and detection of electromagnetic waves

�Computers: Digital Logic

�Lasers: Lights amplification by stimulated emission of radiation

�Production of ultra high magnetic fields: Super conductivity

�Rocket Propulsion: Newton’s laws of motion

�Electric Generation: Faraday’s laws of electromagnetic induction

�Hydroelectric Power: conversion of gravitational potential energy into electrical energy

�Aeroplane: Bernoulli’s principle in fluid dynamics

�Particle Accelerators: Motion of charged particles in elect to magnetic fields

�Sonar: reflection of ultrasonic waves

�Optical Fibres:Total internal reflection of light