“‘ “‘be,’ And It Is” ننُوكنييفي ننكن: Introduction Of Physics

“‘Be,’ and it “‘ is” ‫فييينكوُنن نكنن‬ Introduction of Physics Q: What is Science? Define its main Branches. Ans: The word science derived from the Latin word Scientia, that means to know. – Science is the knowledge that is obtained from the experiments and observations.

Science is subdivided in two main branches:

i) Physical science ii)Biological science Physical science: it is the study of non-living things. This branch of science is further divided into many branches. i.e. Physics, Chemistry, Geology, Astrology, Astronomy etc. Biological science: It is the study of living things. This branch of science is further divided into many branches. i.e. Zoology Botany etc.

Q: What is physics?

Ans: The word physics is taken from the Greek word Phusis or Physikos that means nature, this word was introduced by the ancient scientist Aristotle in the year 350 B.C. – It is the study of matter and energy and the interaction between them. – It is the science that is based on experimental observations and measurements of natural phenomena. MCQS-1 1. The word Science is taken from ____ language: a) Greek b) Latin c) Arabic d) Sindhi 2. The word Science comes from a verb “Scientia” meaning _____. a) Nature b) to, know c) to, think d) N.O.T 3. ______is the knowledge obtained from the observation and experiments. a) Science b) Chemistry c) Both (a) & (b) d) Physics 4. Science is sub divided into : a) Biological Science b) Physical Science c) Both (a) & (b) d) N.O.T 5. Biological Science can be defined as the study of: a) Living things b) Non-living things

c) Both (a) & (b) d) N.O.T 6. Physical Science can be defined as the study of: a) Living things b) Non-living things c) Both (a) & (b) d) N.O.T 7. Physics is the one of the branches of a) Physical Science b) Biological science c) Both (a) & (b) d) N.O.T 8. The word Physics comes a Greek verb “Physikos” meaning __________. a) Nature b) to know c) To think d) N.O.T 9. Physics can be defined as the study of: a) Matter b) Energy c) Both (a) & (b) d) N.O.T 10. _____is based on experimental observations and quantitative measurements. a) Science b) Chemistry c) Both (a) & (b) d) Physics

History of physics Q: Write about History of Physics. Ans: The history of physics is old as the history of mankind. – The first book on physics named as Phusis written by the Greek Philosopher Aristotle. – The Chinese for the first time manufactured paper (papytue). – Egyptian used to measure the flood in the river Nile. – The people of Euphrates and Tigris valleys were aware of calendars and had the knowledge of geometry. – The people of Indus valley or Indians were the pioneers of the decimal system. – Johanne Kepler (1571-1630) presented Kepler’s three law of planetary motion. – Law of inertia given by Galileo-Galilei. – Al- Battani made calculations in connection with solar system, change in season, eclipses of moon and sun. – Archimedes gave law of floatation (buoyancy), and also invented lever and screw. – Al- Khawarizmi was founder of Analytical Algebra and wrote a book “Hisabul-Jubrwal-Muqabla” on Algebra. He also invented the term logarithm (algorithm). – Bertrand Russel remarked that, “Omer Khayyam is the only man Known to me who was both a poet and mathematician”. – Ibn-al-Haitham was a great physicist of the Islamic world, also known as father of modern optics. He wrote book named “Kitab-ul-Manazir” on optics (light). He developed the laws of reflection and refraction. He constructed the pinhole camera. – Al-Razi wrote about 200 original monographs, half of which pertained to medicine. – Abu-Rehan Al- Beruni wrote the book named as “Kitab-ul-Qanoon-ul-Masoodi” is considered as Encyclopedia of astronomy. – Ibn-e-Sina discovered the use of catheters. He invented silver syringe. He wrote two books named as Al-Shifa an encyclopedia of philosophy and Al-Qanun-Fil-Tib (Qanoon) on Medicine. – George Stephenson invented heat engine. – Electron was discovered by J.J .Thomson. – Proton was discovered by Gold Stein. – Neutron was discovered James Chadwick. – Nucleus of atom was discovered by Rutherford. – Wave theory of light was purposed by Huygens. – Corpuscular theory of light was purposed by I. Newton. – X-rays was invented by W. Roentgen. – Radioactivity was discovered by H. Becquerel. – Three laws of motion were given by I. Newton. – Law universal Gravitation was given by I. Newton. MCQS-2 1. Who manufactured paper for the first c) heat engine d) Chemistry time? 4. Who were the pioneers of decimal a) Romans b) Indians system? c) Egyptians d) Chinese a) Romans b) Indians 2. _____ used to measure the flood level c) Egyptians d) Chinese in the river Nile. 5. ………. Made calculations in a) Romans b) India connection with solar system, c) Egyptians d) Chinese change in seasons, eclipses of moon 3. The people of Euphrates and Tigris and sun. valleys were aware of _____. a) Al Battani b) Al Razi a) Calendars b) Decimal c) Bertrand Russell d) I. Newton System Page | 2

6. Who remarked that Omer Khayyam is the only man known to me who was both a poet and mathematician? a) Al Battani b) Al Razi c) Bertrand Russell d) I. Newton 7. Who wrote 200 monographs, half of which pertained to medicine? a) Al Battani b) Al Razi c) Bertrand Russell d) I. Newton 8. George Stephenson invent ……. a) Calendars b) Decimal System c) heat engine d) Chemistry 9. Which one of the following book was written by Ibn-Al- Haitham? a )Kitab –al-Manazir b) Al- Shifa c) Al-Qanoon d) N.O.T10. Law of Reflection and Reflection are given by: a) Al Razi b) Al Beruni c) Ibn-e-Sina d) Ibn –alHaitham 11. Who is known as father of modern optics? a) Al Razi b) Al Beruni c) Ibn-e-Sina d) Ibn –alHaitham 12. _____ was the first to explain that vision occurs when light reflects from an object and then passes to ours eyes. a) Al Razi b) Al Beruni c) Ibn-e-Sina d) Ibn –alHaitham 13. Kitab- al – Manazir is written on _____. a) astronomy b) Philosophy c) Light d) medicine 14. Pinhole Camera was designed by a) Archimedes b) Al Beruni c) Ibn-e-Sina d) Ibn –alHaitham 15. Who invented the silver syringe? a) Ibn –al- Haitham b) Al Beruni c) Ibn-e-Sina d) Al Razi 16. Al Shifa was a book on a) Astronomy b) Philosophy c) Medicine d) Light 17. The Author of the book Al Shifa was: a) Ibn –al- Haitham b) Al Beruni

c) Ibn-e-Sina d) Al Razi 18. Kitab Al Qanoon Fil-Tib was a book on a) Astronomy b) Philosophy c) Medicine d) Light 19. The Author of Al-Qanoon Fil-Tib was: a) Ibn –al- Haitham b) Al Beruni c) Ibn-e-Sina d) Al Razi 20. The circumference of the Earth is calculated by……… a) Ibn –al- Haitham b) Al- Beruni c) Ibn-e-Sina d) Al Razi 21. The Famous Book of Astronomy ‘Kitab-al-Qanoon Al Masoodi’ was written by a) Ibn –al- Haitham b) Al- Beruni c) Ibn-e-Sina d) Al Razi 22. Who gives principle of buoyancy (Floatation) a) Galileo Galleli b) J. Stephenson c) Archimedes d) John Dalton 23. Screw & lever were invented by a) Al Beruni b) Ibn-e-Sina c) Ibn –al- Haitham d) Archimedes 24. Which of the following is Pakistani Scientist? a) Al Beruni b) Ibn-e-Sina c) Abdus Salam d) Archimedes 25. Dr. Abdus Salaam was awarded noble Prize for his work on. a) GUT b) Motion c) Optics d) Wave 26. The first book on analytical Algebra“Hisab-ul-jabrwal-Moqabla” was written by: a) Ibn –al- Haitham b) Al-Khwarizmi c) Al Kindi d) Ibn-e-Sina 27. Al-Khwarizmi invented the term ….. a) Logarithm b) trigonometry c) Geometry d) set 28. The famous Mathematical and the Founder of algebra was………. a)Al-Khwarizmi b) Ibn-e-sina c) Jabir- Bin- Hayan d) Yaqoob-ul-kindi 29. Who gave the theory of relativity? a) Bohar b) Einstein c) Roentgen d) Crooks 30. Who gave law of inertia a) Sir. I. Newton b) Albert Einstein Page | 3

c) Galileo Galleli d) Pascal 31. Who among the following discovered X-rays? a) Marie Curie b) Einstein c) W. C Roentgen d) W. Crooks 32. Who among the following is the credited for the Corpuscular theory? a) Sir. I. Newton b) Pythagoras c) Galileo d) J. Kepler 33. Nucleus of an atom is discovered by_____. a) Bohar b) Einstein c) Rutherford d) Crooks

34. Phenomena of Radioactivity are proposed by_____. a) H. Becquerel b) Einstein c) Roentgen d) Crooks 35. Who made nuclear power to Pakistan? a) Dr. Abdul Qadeer b) Ibn-e-Sina c) Abdus Salam d) Archimedes 36. Law of Planetary Motion was presented by : (a) Newton b) Pythagoras c) Galileo d) J. Kepler

Branches of Physics Q: Define the branches of physics. Ans: There are two main branches of physics: i) Classical physics ii)Modern physics Classical physics or Newtonian physics – Classical physics took form when Newton developed his theory of gravity and the mathematics we commonly known as calculus. – Refers to the traditional forces that were recognized and developed before the beginning of the 20th century. – Newtonian physics were three dimensional: width, height and depth. – Physics that is based on Newton's laws of motion and does not make use of quantum mechanics and the theory of relativity. Branches related with Classical physics: 1. Mechanics is concerned with motion of bodies with or without the influence of force. It is divided into statics, kinematics and dynamics. – Statics: Study of bodies at rest. – Kinematics: Study of motion of bodies without regard to its causes. – Dynamics: Study of motion and the forces that affect it. 2. Thermodynamics is study of the laws governing the transformation of heat energy to and from other forms of energy. – It describes how thermal energy is converted to and from other forms of energy and how it affects matter. 3. Electromagnetism An electric current gives rise to a magnetic field and a changing magnetic field induces an electric current. – The branch of physics that deals with electricity and magnetism. 4. Acoustics It concerned with the production, control, transmission, reception, and effects of sound. – The term is derived from the Greek akoustos, meaning “hearing.” 5. Optics is the study of light, is concerned not only with visible light but also with infrared and ultraviolet radiation, which exhibit all of the phenomena of visible light except visibility, e.g., reflection, refraction, interference, diffraction, dispersion, and polarization of light. Optics is divided into two categories: Page | 4

– Physical optics: It deals with the production, nature and properties of light. – Geometrical optics: It deals with the reflection and refraction of light as encountered in the study of mirrors and lenses. 6. Electrostatics deals with electric charges at rest and their effect. 7. Electrodynamics deals with moving electric charges and their effects. 8. Hydrodynamics deals with the motion of fluids and the forces acting on solid bodies immersed in fluids and in motion relative to them. Modern Physics – Modern physics is a branch of physics in which matter and energy are not separate, but instead are alternate forms of one another. – Modern physics refers those developments which are after the 20 th century. – It deals with Space (width, height and depth) and time. Branches related with modern physics 1. Atomic Physics is concerned with the structure and properties of the fundamental particles of atoms. 2. Nuclear Physics is the study of the reactions, structure, and behavior of the nucleus in the atom. 3. Quantum Physics is the study of the discrete nature of phenomena at the atomic and subatomic levels. 4. Solid State Physics is the study of structure and all properties of solid materials. 5. Plasma Physics is concerned with the properties of highly ionized particles. MCQS-3 1. The branch of physics deals with the study of production and propagation and properties of Sound: a) Optics b) Acoustics c) Astro Physics d) Bio Physics 2. The branch of physics deals with the study of highly ionized particles: a) Nuclear physics b) Acoustics c) Plasma Physics d) Bio Physics 3. The branch of physics deals with the study of electric Charges at rest: a) Optics b) Solid state physics c) Astro Physics d) Electrostatics 4. The branch of physics deals with the study of electric Charges at motion: a) Classical physics b) Electrodynamics c) Electricity d) Both (b) & (c) 5. The branch of physics deals with the study of motion of bodies with or without influence of force: a) Mechanics b) Acoustics c) Astro Physics d) Bio Physics

6. The branch of physics deals with the study of motion of bodies in air: a) Optics b) Aerodynamics c) Heat d) Medical Physics 7. The branch of physics deals with the study of motion of bodies in water: a) Optics b) Acoustics c) Hydrodynamics d) Bio Physics 8. The branch of physics deals with the study of properties of matter specially solid states: a) Optics b) Acoustics c) thermal Physics d) Solid State Physics 9. The branch of physics deals with the study of nucleus of atom and reaction with nucleus: a) Optics b) Acoustics c) Nuclear Physics d) Bio Physics 10. The branch of physics deals with the study of atom and its fundamental particles: a) Molecular Physics b) Acoustics c) Atomic Physics d) Both (a) & (c)

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11. The branch of physics deals with the study of physical methods and techniques related with life: a) Bio Physics b) Medical Physics c) Astro Physics d) Both (a) & (b) 12. The branch of physics deals with the study of stars and galaxies: a) Optics b) Acoustics c) Astro Physics d) Bio Physics 13. The branch of physics deals with the study of relation with electricity and magnetism: a) Optics b) Acoustics c) Electromagnetism d) Bio Physics 14. The branch of physics deals with the study of light: a) Optics b) Acoustics c) Astrophysics d) Bio Physics 15. The branch of physics deals with the study of properties of light: a) Physical Optics b) Geometrical Optics

c) Astro Physics d) Bio Physics 16. The branch of physics deals with the study of application , geometry and instruments of light: a) Physical Optics b) Geometrical Optics c) Astro Physics d) Bio Physics 17. The branch of physics deals with the study of low voltage and low current devices: a) Physical Optics b) Geometrical Optics c) Electronics d) Bio Physics 18. The branch of physics deals with the study of conversion of heat into and from others form of energy: a) Physical Optics b) Geometrical Optics c) Astro Physics d) Thermodynamics

Measurement Q: What are the physical quantities? Define types of physical quantities. Ans: Those quantities which can be compared and measured. i.e length, mass, time, pressure, temperature, electric current, force etc Representation of physical quantity: – A physical quantity is represented completely by its magnitude and unit. – For example, 10 meter means a length which is ten times the unit of length. Here 10 represent the numerical value of the given quantity and meter represents the unit of quantity under consideration. Thus in expressing a physical quantity we choose a unit and then find that how many times that unit is contained in the given physical quantity, i.e. Physical quantity (Q) = Magnitude × Unit = n × u – Where, n represents the numerical value and u represents the unit. Thus while expressing definite amount of physical quantity, it is clear that as the unit (u) changes, the magnitude (n) will also change but product ‘nu’ will remain same. e.g., acceleration due to gravity, g = 32 ft/s2 = 9.8 m/s2 – Magnitude of a physical quantity and units are inversely proportional to each other .Larger the unit, smaller will be the magnitude. Physical quantities are divided into two types: i. Fundamental Quantities ii. Derived quantities 1. Fundamental Quantity is any physical quantity which has own definition and explanation and independent of other quantity. – Initially, only these fundamental quantities – length, mass and time were considered. – With the development of science, four more physical quantities were added these are temperature, electric current, luminous intensity and amount of substance. Page | 6

2. Derived quantity is any quantity which is obtained from fundamental quantity. i.e speed, acceleration, force, density etc.

Q: What are physical units? And define its types. Ans: Physical Units: The reference standard used for the measurement of a physical quantity is called the unit of that physical quantity.

There are two types of physical units: i. Fundamental units: The units used to measure fundamental quantities are called fundamental units. ii. Derived units: The units of derived quantities which depend on fundamental units for their measurements are called derived units.

Q: What is system of units? Explain different types of systems of units. Ans: System of units – Units are classified as fundamental units and derived units. In 1832, Gauss had suggested to select any three physical quantities as fundamental quantities. Accordingly, many systems of units came into existence. – The whole set of units i.e., all the basic and derived units taken together forms a system of units.

System of units is classified mainly into four types: Following system of units are applicable in only Mechanics. i. CGS system ii. MKSA System iii. FPS System iv. SI system of units is applicable to the whole of physics.

C.G.S. system: – The system is also called Gaussian system of units. – It stands for Centimeter-Gram-Second system. – In this system, fundamental quantities i.e., length, mass and time are measured in centimeter, gram and second respectively. – It is an old French metric system of unit. – In this force has derived unit called as dyne.

M.K.S. system:

– The system is also called Giorgio system. – It stands for Meter-Kilogram-Second system. – In this system, fundamental quantities i.e. length, mass and time are measured in metre, kilogram and second respectively. – It is a French metric system of unit. – In this system force has derived unit called as newton

F.P.S. system: – – – – –

The system is also called British Engineering system or costmary system. It stands for Foot-Pound-Second system. In this system, length, mass and time are measured in foot, pound and second respectively. In this system mass has derived unit called as slug. It is a British imperial system.

S.I. system:

– In October 1960, at the Eleventh International General Conference of weights and measures in Paris, a common system of units was accepted. Page | 7

– This system of units called “Systeme Internationale d Units” is the modern metric system of unit measurement. It is abbreviated as S.I. units. – S.I. units consist of seven fundamental units, two supplementary units and a large number of derived units. – Nowadays, S.I. system has replaced all the other systems of units and is greatly used to exchange scientific data between different parts of the world.

Physical quantity

Unit

Symb ol

Length

Meter

M

Mass

Kilogram

Kg

Time

Second

S

Electric current

Ampere

A

Temperature

Kelvin

K

Luminous intensity

Candela

Cd

Amount of substance

Mole

Mol

Radian

Rad

Stredian

Sr

Fundamental Quantities

Supplementary Units Plane angle Solid Angle

Following conventions should be followed while writing units of physical quantities: i. For a unit derived from the name of a person, the symbol or first letter of the symbol is a capital letter. For example, N for newton, J for joule, W for watt, Hz for hertz. Symbols of the other units are not written with capital initial letter. ii. Unit names, including units named after a person are written in lower – case. Example: unit of force is written as newton and not as Newton; unit of power is written as watt and not as Watt, symbol for meter is ‘m’, for second is ‘s’, for kilogram is ‘kg’ iii.Symbols of units are not to be expressed in plural form. For example, 10 meters is written as 10 m and not as 10 ms. This is because, 10 ms, means 10 millisecond. The unit is always written in singular form, e.g., foot not feet. iv. No punctuation marks are used after unit, e.g., sec not sees.

Definition of some important SI units

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1) Meter: A meter is equal to 1650763.73 times the wavelength of the light emitted in vacuum due to electronic transition from 2p 10 state to 5d5 state in Krypton-86. But in 1983, 17th General Assembly of weights and measures adopted a new definition for the meter in terms of velocity of light. According to this definition, a meter is defined as the distance traveled by light in vacuum during a time interval of 1/299, 792, 458 of a second. 2) Kilogram: The mass of a cylinder of platinum-iridium alloy kept in the International Bureau of weights and measures preserved at Serves near Paris is called one kilogram. 3) Second: A second is the duration of 9192631770 periods of radiation corresponding to the transitions between two hyperfine levels of the ground state of cesium-133 atom. 4) Ampere is the current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross section, and placed 1 meter apart in vacuum would produce between the conductors a force equal to 2 * 10 -7 newton per meter of length. 5) Candela is the luminous intensity, in the perpendicular of a surface 1/600000 square metre of a black body at the temperature of freezing platinum under a pressure of 101325 newton per square metre. 6) Kelvin, the unit of thermodynamics, is 1/273.16 of the thermodynamics temperature of the triple point of water. 7) Mole is the amount of substance of a system which contains as many elementary entities as there re atoms in 0.012 kilogram of carbon-12. 8) Radian: The angle made by an arc of the circle equivalent to its radius at the center is known as radian. 1 radian = 57o17l45ll. 9) Steradian: The angle subtended at the center by one square meter area of the surface of a sphere of radius one meter is known as steradian. MCQS-4 1. To measure physical quantity is called a) Experiment b) Measurement c) Observation d) hypothesis 2. ____is quantity which can be measure and compared. a) Chemical Quantity b) Neutral Quantity c) Physical quantity d) Biological Quantity 3. Physical quantity is divided into: a) Fundamental quantity b) Derived Quantity c) both (a) & (b) d) chemical quantity 4. Any physical quantity which has own definition and explanation and independent of other quantity is known as a) Fundamental Quantity b) derived quantity c) Supplementary Quantity d) N.O.T 5. Any quantity which is obtained from fundamental quantity is called as: a) Fundamental Quantity b) derived quantity c) Supplementary Quantity d) N.O.T 6. Basically _____ are fundamental quantity a) Length b) mass c) Time d) A.O.T

7. A standard in the form of which a physical quantity is to be measured is known as____. a) Physical Units b) Chemical Units c) Supplementary Units d) N.O.T 8. The units of fundamental quantities are called ………..units. a) Fundamental b) derived c) Supplementary d) N.O.T 9. The units of derived quintiles are known as_____ units a) Fundamental b) derived c) Supplementary d) Basic 10. System of units is the set of …….. a) Fundamental Units b) Derived units c) Both (a) & (b) d) N.O.T 11. Number of systems of units are: a) 1 b) 2 c) 3 d) 4 12. _____system of units is applicable to the whole of physics. a) SI b) MKS c) CGS d) FPS 13. Which of the system of units is / are applicable in Mechanics. a) MKS b) CGS c) FPS d) A.O.T Page | 9

14. A in CGS the fundamental units of length, mass and time are ______ respectively: a) centimeter, kilogram, second b) centimeter, gram, second c) meter, kilogram, second d) meter, gram, second 15. In CGS system ….. has derived unit a) Force b) mass c) Length d) Time 16. In CGS system the unit of force is: a) Slug b) dyne c) newton d) ampere 17. A in FPS the fundamental units of length, force and time are ______ respectively: a) centimeter, kilogram, second b) foot, pound, second c) meter, kilogram, second d) meter, gram, second 18. FPS system is also called: a) BE system b) Customary System c) both (a) & (b) d) N.O.T 19. In FPS system ….. has derived unit: a) Force b) mass c) Length d) Time 20. In FPS system the unit of mass is a) Slug b) dyne c) newton d) ampere 21. A in MKSA the fundamental units of length, mass, time and electric current are ______ respectively: a) centimeter, kilogram, second, kelvin b) centimeter, gram, second, coulomb c) meter, kilogram, second, ampere d) meter, gram, second, newton 22. In MKSA system ….. is derived quantity. a) Force b) mass c) Length d) Time 23. In MKSA system the unit of force is a) Slug b) dyne c) newton d) ampere 24. Number of base SI units are : a) 4 b) 7 c) 3 d) 5 25. Which of following is not a fundamental unit in S.I system : a) Kelvin b) mole c) candela d) coulomb

26. Candela is the unit of : a) Electric intensity b) luminous intensity c) Electric current d) temperature 27. kelvin is the unit of : a) Electric intensity b) luminous intensity c) Electric current d) temperature 28. ampere is the unit of : a) Electric intensity b) luminous intensity c) Electric current d) temperature 29. Mole is the unit of : a) Amount of Substance b) Electric Current c) Luminous Intensity d) temperature 30. Meter per second (m/s) is the unit of a) Velocity b) speed c) angular velocity d) both (a) & (b) 31. Meter is the unit of _____. a) Distance b) displacement c) radius d) A.O.T 32. The unit of acceleration is same as unit of_____. a) Velocity b) gravity c) angular velocity d) both (a) & (b) 33. The unit of momentum is_____. a) N.m b) N.s c) Kg.m/s d) Both (b) & (c) 34. Erg is the unit of : a) Force b) Energy c) Momentum d) Mass 35. Which of the following quantity is unit less : a) Specific Gravity b) strain c) co-efficient of friction d) A.O.T 36. The Unit of PV equivalent to _________: where P is pressure and V is volume is : a) Joule b) N.s c) N.m2 d) N/m 37. The unit of solid angle is : a) stredian b) radian c) Hertz d) Diopters 38. The unit of plane angle is : a) stredian b) radian c) Hertz d) Diopters 39. Which of the following is/ are the unit of length a) Fermi b) Angstrom c) micron d) A.O.T Page | 10

2 40. If x=a+ bt +ct where x is in meter and t in second, what is the unit of c? a) m / s 2 b) m/s c) newton d) Joule 41. Light year is a unit of: a) Time b) mass c) Distance d) Energy 42. The unit of Planck's constant is: a) Joule b) Joule/s c) Joule/m d) Joule .s 43. Kg. m/sec is equivalent to : a) N/s b) J.m c) N.s d) N.m 44. The unit of energy is same as the unit of a) Power b) momentum c) work d) force 45. The unit of force is ____and its symbol is ____which is the correct pair? a) Newton, n b) Newton, N c) newton, n d) newton, N 46. Which one is the correct representation of unit of pressure? a) Newton / Meter 2 b) newton /

meter

2

c) Newton /

Meter

2

meter

2

d)

newton/

47. Which of following is SI base unit? a) gram b) slug c) newton d) Kilogram 48. Which of the following is not unit of time? a) hour b) nano Second c) minute d) light year 49. Dyne-sec stands for the unit of a) power b) momentum c) energy d) force 50. Which of the following is the proper combination for force a) kg b) m/s 2 c) Kg∙ m 2 /s 2 d) Kg∙ m/s 2 51. The unit of angular acceleration in the SI system is a) N /kg b) m/s 2 c) rad /s 2 d) N ∙ m/ kg 52. N/kg is the unit of: a) acceleration b) momentum c) velocity d) force 53. Which of the following is equivalent to one pascal of gas pressure?

a) Kg∙ m 2 /s 3 b) kg m/ s2 c) Kg∙ m 2 / s 2 d) Kg/m s2 54. The unit having no dimensions is known as _____units a) Fundamental b) Derived c) Supplementary d) N.O.T 55. Which of the following has not been expressed in proper units? a) momentum = Kg∙ m/s b) power =

Kg∙ m 2 /s 3

c) power = Kg∙ m 2 /s

Kg/m∙ s

d) pressure =

2

56. Unit of density in SI is: a) Kg/m 3 b) pascal 3 c) m/kg d) A.O.T 57. Which of the following system of unit is not based on only units of mass length and time? a) SI b) MKS c) CGS d) FPS 58. Which of the following symbol of unit does not follow practical norms for the use of SI system? a) Kg b) kg. c) k d) A 59. The unit of universal gravitational constant is............... a) Kg∙ m/s 2 b) N ∙ m−1 /s 2 2 2 c) N ∙ m /kg d) N ∙ m/kg 60. Joule/sec is the unit of............... a) power b) pressure c) angular momentum d) Energy 61. The force F is represented by equation F=pl + ql , where l is the length. The unit of p is same as that of............... a) Surface tension b) velocity c) force d) momentum 62. Write the unit of surface tension in SI system. (a) N ∙ m b) N ∙ m−1 c) dyne ∙ cm d) N ∙ m 2 63. Which physical quantity has unit of pascal - second? a) Velocity b) viscosity c) coefficient of viscosity d) energy 64. Which physical quantity has unit of joule - second? a) velocity b) plank’s constant c) energy d) viscosity Page | 11

2 65. Equation of force F=at + b t where F is force in Newton t is time in second, then write unit of b. a) N ∙ s−1 b) N ∙ s2

c) N ∙ s d) N ∙ s−2 66. Watt. Sec is equivalent to : a) N /m b) Kg∙ m 2 /s 2 c) N ∙ m d) Both (b) & (c)

Dimension Q: What is dimension? Ans: The concept of physical dimension was introduced by Joseph Fourier in 1822. – The powers to which fundamental quantities must be raised in order to express the given physical quantity are called its dimensions. – It is an expression that relates derived quantity to fundamental quantities. But it is not related to the magnitude of the derived quantity. – The way in which the derived quantity is related to the basic quantity can be shown by the dimensions of the quantity. – It is used denoted the nature of physical quantity. – If ‘A’ is any physical quantity then the dimensions of A are represented by [A]. – Mass, length and time are represented by L, M and T respectively, therefore the dimension of the fundamental quantities are as follows [Mass]= [M] [Length]= [L] [Time] = [T] Q: Define types of variables and constants.

Ans: i. Dimensional variables

The quantities like area, volume, velocity, force etc. posses dimensions and do not have a constant value. Such quantities are called dimensional variables. ii. Non dimensional quantities The quantities like strain, angle, specific gravity, are ratios which are mere numbers are dimensionless quantities and are called numeric. They have neither dimension nor constant value; they are called non dimensional variables. iii. Dimensional constants The quantities like Gravitational constant G, the velocity of light c and plank’s constant h have dimensions and constant value. They are called dimensional constant. iv. Non- dimensional constants The quantities which have no dimensions but have constant value are called non- dimensional constants. 1, 2, 3……, pi are non dimensional constant. Q: What is law homogeneity of dimensions? Ans: In any correct equation representing the relation between physical quantities, the dimensions of all the terms must be the same on both sides. Terms separated by ‘+’ or ‘–’ must have the same dimensions.

Q: Write the uses of dimensions. Ans: Dimension is used to: – To check the correctness of a physical quantity. – By the principle of homogeneity of dimensions, the dimension of all terms on the sides of an equation must be the same. – To find the unit of a given physical quantity in a given system of units – To find dimensions of physical constants or coefficients – To convert a physical quantity from one system of units to another – To check the dimensional correctness of a given physical relation Page | 12

Q: What are the limitations of Dimensions? Ans: The limitations of dimensions are: – Dimensionless quantities cannot be determined by this method. Constant of proportionality cannot be determined by this method. They can be found either by experiment (or) by theory. – This method is not applicable to trigonometric, logarithmic and exponential functions. – In the case of physical quantities which are dependent upon more than three physical quantities, this method will be difficult. – In some cases, the constant of proportionality also possesses dimensions. In such cases, we cannot use this system. – If one side of the equation contains addition or subtraction of physical quantities, we cannot use this method to derive the expression.

Some Quantities having Same Dimensions S.

Dimensi on

Quantity

1

[M0 L T0]

2 3 4 5

[M0 L-1 T0] [M0 L T-1] [M0 L0 T-1] [M L2 T-2]

6 7 8 9 10 11

[M L-1 T-2] [M L T-1] [M L T-2] [M L0 T-2] [M L2 T-1] [M0 L0 T0]

Length, distance, radius, diameter, focal length, angstrom, moment arm, wavelength Power of lens, wave number, rydberg constant. Speed, velocity, orbital velocity, terminal velocity, drift velocity Frequency, angular frequency, angular velocity, decay constant Work, internal energy, potential energy, kinetic energy, torque, moment of force. Pressure, stress, young’s modulus, bulk modulus, energy density. Impulse, momentum. Thrust, force, weight, tension, Normal reaction, centripetal force. Surface tension, surface energy, elastic constant. Angular momentum, plank’s constant. Strain, refractive index, relative density, angle, solid angle, relative permittivity (dielectric constant)

N o

Units and Dimension Formula of some important quantities S.

Physical quantity

FPS units

CGS units

MKS units

SI Units

Dimension

ft2 ft3 Slug/ft3 ft/s

cm2 cm3 gm/ cm3 cm/s

m2 m3 Kg/ m3 m/s

m2 m3 Kg/ m3 m/s

[L2] [L3] [M L-3] [L T-1]

5 6 7 8

Area Volume Density Speed Velocity Acceleration Force Momentum power

cm/s2 Dyne Dyne. second Erg/s

m/s2 newton N.s J/s or W

m/s2 newton N•s Watt

[L T-2] [M L T-2] [M L-1 T-1] [M L2 T-3]

9 10

Length (l) Distance

ft/s2 Pound (lb) lb.s Horse power Foot (ft) Ft

cm cm

m m

m m

[L ] [L ]

N o 1 2 3 4

or

Page | 13

11 12 13 14 15 16 17 18 19 20 21 22 23

Energy Mass Time Specific gravity Gravity Stress Pressure Strain Torque Angular momentum Frequency Angular velocity Work

ft • lb Slug Second (s) No unit ft/s2 lb/ft2 lb/ft2 No unit ft • lb Ft •lb • s

Erg Gram Second

Joule Kilogram Second

Joule Kilogram Second

[M L2 T-2] [M ] [T]

cm/s2 Dyne/cm2 Dyne/cm2

m/s2 N/m2 N/m2

m/s2 N/m2 N/m2

[L T-2] [M L-1 T-2] [M L-1 T-2]

Dyne • cm Erg • s

N•m J•s

N•m J•s

[M L2 T-2] [M L2 T-1]

Cycle/ s Rad/s ft • lb

Cycle/s Rad/s Erg

Cycle/s Rad/s joule

Hertz (Hz) Rad/s joule

[T-1] [ T-1] [M L2 T-2]

MCQS-5 1. The dimension of angular displacement is a) [M L T-1] b) [ML3T-1] c) [Mo Lo To] d) [ML-1T-1] 2. The dimension of angular acceleration is a) [MLT-1] b) [ML3T-1] o o -2 -1 -1 c) [M L T ] d) [ML T ] 3. The dimension of displacement is a) [MoL1To] b) [ML3T-1] o o -1 c) [M L T ] d) [ML-1T-1] 4. The dimension of velocity is a) [MLT-1] b) [ML3T-1] c) [MoLoT-1] d) [MoL1T-1] 5. The dimension of acceleration is a) [MLT-1] b) [ML3T-1] o 1 -2 -1 -1 c) [M L T ] d) [ML T ] 6. The dimension of force is a) [MLT-2] b) [ML3T-1] o o -1 -1 -1 c) [M L T ] d) [ML T ] 7. The dimension of momentum is a) [MLT-1] b) [ML3T-1] o o -1 -1 -1 c) [M L T ] d) [ML T ] 8. The dimension of torque is a) [MLT-1] b) [ML2T-2] o o -1 -1 -1 c) [M L T ] d) [ML T ] 9. The dimension of work is a) [MLT-1] b) [ML2T-2] c) [MoLoT-1] d) [ML-1T-1] 10. The dimension of kinetic energy is a) [MLT-1] b) [ML3T-1] o o -1 c) [M L T ] d) [ML2T-2] 11. The dimension of potential energy is a) [MLT-1] b) [ML2T-2]

c) [MoLoT-1] d) [ML-1T-1] 12. The dimension of angular momentum is a) [MLT-1] b) [ML2T-1] o o -1 c) [M L T ] d) [ML-1T-1] 13. The dimension of power is a) [MLT-1] b) [ML2 T-3] o o -1 c) [M L T ] d) [ML-1T-1] 14. The dimension of intensity of sound is a) [MLT-1] b) [ML3T-1] 0 -3 c) [M L T ] d) [ML-1T-1] 15. The dimension of elastic constant or spring constant is a) [MLT-1] b) [ML3T-1] o -2 c) [M L T ] d) [ML-1T-1] 16. The dimension of moment of inertia is a) [MLT-1] b) [ML3T-1] 2 O c) [M L T ] d) [ML-1T-1] 17. The dimension of impulse is a) [MLT-1] b) [ML3T-1] o o -1 c) [M L T ] d) [ML-1T-1] 18. The dimension of pressure is a) [MLT-1] b) [ML3T-1] o o -1 c) [M L T ] d) [ML-1T-2] 19. The dimension of density is a) [MLT-1] b) [ML3T-1] c) [M L-3 T0] d) [ML-1T-1] 20. The dimension of Gravitational Constant is a) [MLT-1] b) [ML3T-1] -1 3 -2 -1 -1 c) [M L T ] d) [ML T ] 21. The dimension of Coefficient of viscosity is Page | 14

a) [MLT-1] b) [ML3T-1] o o -1 c) [M L T ] d) [ML-1T-1] 22. The dimension of stress is a) [MLT-1] b) [ML3T-1] o o -1 c) [M L T ] d) [ML-1T-2] 23. The dimension of time period is a) [MLT-1] b) [ML3T-1] c) [MoLoT1] d) [ML-1T-1] 24. The dimension of frequency is a) [MLT-1] b) [ML3T-1] o o -1 c) [M L T ] d) [ML-1T-1] 25. The dimension of heat is a) [MLT-1] b) [ML2T-2] o o -1 c) [M L T ] d) [ML-1T-1] 26. The dimension of plank’s constant is a) [MLT-1] b) [ML3T-1] c) [MoLoT-1] d) [ML-2T-1] 27. The dimension of volume is a) [MLT-1] b) [MoL3To] o o -1 c) [M L T ] d) [ML-1T-1] 28. The dimension of area is a) [MLT-1] b) [MoL2 To] o o -1 c) [M L T ] d) [ML-1T-1] 29. Which of the following does not have the same dimension? a) Electric flux, electric field, electric dipole moment b) pressure, stress, young’s modulus c) Electromotive force, potential difference, electric voltage d) Heat, potential energy, work 30. The dimension of angular velocity is a) [MLT-1] b) [ML3T-1] o o -1 c) [M L T ] d) [ML-1T-1] -2 31. [MLT ] is an expression for a) weight b) Normal Reaction c) drag force d) A.O.T 32. [MoL-1 To] is an expression for a) wave number b) power of lens c) Rydberg constant d) A.O.T -1 o 33. [ML T ] is an expression for a) linear density b) areal density c) density d) A.O.T 34. [MoLT-2] is an expression for a) gravity b) acceleration c) Force/mass d) A.O.T 35. [ML2T-2] is an expression for a) force × displacement b) power × time c) torque d) A.O.T 36. [MoLoTo] is an expression for

a) refractive index b) relative density c) π d) A.O.T o -2 37. [ML T ] is an expression for a) surface tension b) spring constant c) surface energy d) A.O.T 38. The dimension of sine is a) [MLT-1] b) [ML3T-1] c) [MoLoTo] d) [ML-1T-1] 39. The dimension of surface energy is a) [MLT-1] b) [ML3T-1] o -2 c) [M L T ] d) [ML-1T-1] 40. The dimension of linear density is a) [MLT-1] b) [ML3T-1] o o o c) [M L T ] d) [ML-1To] 41. The dimension of tension is a) [MLT-2] b) [ML3T-1] c) [MoLoTo] d) [ML-1T-1] 42. The dimension of retardation is a) [MLT-1] b) [ML3T-1] o -2 c) [M L T ] d) [ML-1T-1] 43. The dimension of areal velocity is a) [MLT-1] b) [ML3T-1] o 2 -1 c) [M L T ] d) [ML-1T-1] 44. IF X times speed equals power, write the dimensional formula for X. a) [MLT-2] b) [ML3T-1] c) [Mo L2 T-1] d) [ML-1T-1] 45. The dimension of angular momentum similar to that of. a) Plank’s Constant b) Impulse c) Force d) Energy 46. The dimension of momentum similar to that of. a) Plank’s Constant b) Impulse c) Force d) Energy 47. The dimension of weight similar to that of. a) Plank’s Constant b) Impulse c) Force d) Energy 48. The dimension of distance similar to that of. a) Plank’s Constant b) Impulse c) Force d) length 49. The dimension of gravity similar to that of. a) Plank’s Constant b) Impulse c) Acceleration d) Energy 50. The dimension of surface tension similar to that of. a) spring constant b) Impulse c) Force d) Energy Page | 15

51. The dimension of work similar to that of. a) Plank’s Constant b) Impulse c) Force d) Energy 52. The dimension of strain similar to that of. a) Plank’s Constant b) stress c) coefficient of friction d) Force 53. Which of the following dimensionless constants: a) Gravitational constant b) Planck's constant c) 4 d) strain 54. Which of the following non dimensional variables: a) Gravitational constant b) Planck's constant c) density d) strain 55. Which of the following nondimensional variables: a) Gravitational constant b) Planck's constant c) density d) angular displacement 56. Which of the following quantities is dimensionless: a) Gravitational constant b) Planck's constant c) density d) refractive index 57. Which of the following quantities is dimensionless: a) Gravitational constant b) Planck's constant c) relative density d) density 58. Which of the following quantities is dimensionless: a) Gravitational constant b) Planck's constant c) 1/2 d) force

59. Which of the following quantities is dimensionless: a) Gravitational constant b) 4 π c) density d) length 60. Which of the following is dimensional variable: a) Gravitational constant b) Planck's constant c) density d) strain 61. Which of the following is the proper combination of force? a)

kg

b) 2

c)

kg ∙ m 2 s

d)

m 2 s

kg ∙ m s2

62. Which of the following physical quantities is of different kind from the rest? a) stress b) pressure c) strain d) young’s Modulus 63. Which of the following does not represent a non-dimensional variable? a) angular displacement b) specific gravity c) radian d) length 64. Which of the following physical quantities is of different kind from the rest? a) stress b) 4 π c) density d) length 65. [ML2T-2] is an expression for a) force × displacement b) power × time c) nRT d) A.O.T 66. dimension of log x is or ex a) [MLT-1] b) [ML3T-1] o o c) [M L T ] d) [ML-1T-1]

Errors Q: Define error and its types. Ans: Error is the difference between actual value and calculated value of any physical quantity. – The uncertainty in measurement is called error. Page | 16

Sources of errors in physics All measurements of physical quantities are uncertain and imprecise to some limit. There are three sources of errors. – Negligence or inexperience of a person. – Faulty apparatus. – Inappropriate method or technique. Types of errors in physics There are two major types of errors in measurement of physical quantities. i. Random error ii. Systematic error Random error: – Random error is said to take place when repeated measurements of the quantity, gives different values under the same conditions. – Random errors in experimental measurements are caused by unknown and unpredictable changes in the experiment. These changes may occur in the measuring instruments or in the environmental conditions. Reasons of random errors: It is occurs due to some unknown reasons. Q: How can we reduce random error? Ans: The random error can be reduced by taking several readings of same quantity and then taking their mean value. Systematic error: – Systematic errors occurs when all the measurements of physical quantities are affected equally, these give consistent difference in the readings. Reasons of systematic errors: The systematic errors may occur due to: – Zero error in measuring instrument – Poor calibration of instrument – Incorrect calibration on the measuring instruments. Q: How can we reduce systematic errors? Ans: We can reduce systematic errors by comparing the instrument with another instrument which is known to be more accurate. Thus, systematic error is reduced by applying a correction factor to all the reading taken on an instrument. Q: How to express an error? Ans: There are three ways of expressing error: i. absolute error ii. relative error iii. percentile error 1. Absolute Error is the amount of error in your measurements. – The absolute error is defined as the absolute value (or magnitude) of the difference between the measured value and the true value. Formula 

xa = the absolute error Page | 17



xm = the measured value



xt = the true value

The formula for computing absolute error is: xa = | xm - xt | 2. Relative Error is the ratio of mean absolute error and the actual value. – The relative error is defined as the absolute error relative to the size of the measurement. – All you need to do is divide the absolute error by the measured value. In addition to the variables, let: er = the relative error Then the formula for computing relative error is: er = ea / xm – You first need to determine absolute error to calculate relative error. Relative error expresses how large the absolute error is compared with the total size of the object you are measuring. – Relative Error = Absolute Error / Known Value Percentile error is the product of relative error with 100. – This is the formula for "Percentage Error": |Approximate Value − Exact × Value| 100 % |Exact Value| – Percent error is related to absolute error and relative error. The difference between an experimental and known value is the absolute error. When you divide that number by the known value you get relative error. Percent error is relative error multiplied by 100%.

Errors in Addition and Subtraction Let (a ± Δa) and (b ± Δb) be two quantities. Suppose x = (a ± Δa) ± (b ± Δb) Then error in x i.e. Δx = ±(Δa+Δb) Hence errors add up under addition or subtraction.

Errors in Multiplication and Division Let x = (a ± Δa)×(b ± Δb) or x = (a ± Δa)/(b ± Δb) Then the relative error in x is given by: Δx/x = ±[(Δa/a + Δb/b)]

Errors in power Let X = An then Δx/x = n ΔA/A

Significant figures Q: What are significant figures? Page | 18

Ans: A Significant Figure or number is a number or digit, which tells how accurate and precise our measurement is. Measuring anything requires a specific type of measuring instrument. Significant Figures make measurements easy and state them precisely. – Any digit which is known with certainty. Rule for determining number of significant figures – All non-zero digits are significant. For example, 866 has three significant figures and 0.866 also has three significant figures.. – Zeros to the left of the first non-zero digit in the number are not significant. For example, 0.008 has only one significant figure and 0.0085 has two significant figures. – Zeros between non-zero digits are significant. For example, 3.05 has three significant figures. – Zeros to the right of the decimal point are significant. For example, 6.00, 0.60 and 0.6000 have 3, 2 and 4 significant figures. – If a number ends with zeros that does not have decimal, the zeros are not significant. For example: 3800 has two significant figures. Q: What is meaning of round off data Ans: Rounding Off means to reduce or to remove. We round off numbers to reduce significant figure and give more precise answers. The rules employed for rounding off a number to the required number of significant digit are as follows  If the digit to be removed is more than 5, the digit to be retained is increased by one. for example, 2.486 If we have to remove 6, we have to round it to 2.49  If the digit to be removed is less than 5, the digit to be retained i.e. preceding number is not changed. For example, 5.334 if 4 is to be removed, then the result is rounded upto 5.33.  If the rightmost digit to be removed is 5, then the preceding number is not changed if it is an even number but it is increased by one if it is an odd number. For example, if 7.35 is to be rounded by removing 5, we have to increase 3 to 4 giving 7.4 as the result. However, if 7.25 is to be rounded off it is rounded off to 7.2.

Some Important Conversions 

1 bar = 106 dyne/cm2 = 105 Nm-2 = 105 pascal



76 cm of Hg = 1.013×106 dyne/cm2 = 1.013×105 pascal = 1.013 bar.



1 toricelli or torr = 1 mm of Hg = 1.333×10 3 dyne/cm2 = 1.333 millibar.



1 kmph = 5/18 ms-1



1 dyne = 10-5 N,



1 kg = 2.205 pounds



1 inch = 2.54 cm



1 mile = 1.61 km



1 liter = 1 dm3 Page | 19



1 newton = 105 dyne



1 pound = 4.4 N



1BTU = 1055 joule = 252 cal



1 H.P = 746 watt



1 kilowatt hour = 36×105 J



1 kgwt = g newton



1 calorie = 4.2 joule



1 electron volt = 1.602×10-19 joule



1 erg = 10-7 joule

Some Important Physical Constants 

Velocity of light in vacuum (c) = 3 × 108 ms-1



Velocity of sound in air at STP = 331 ms-1



Acceleration due to gravity (g) = 9.81 ms-2



Avogadro number (N) = 6.023 × 1023/mol



Density of water at 4oC = 1000 kgm-3 or 1 g/cc.



Absolute zero = -273.15oC or 0 K



Atomic mass unit = 1.66 × 10-27 kg



Quantum of charge (e) = 1.602 × 10-19 C



Stefan’s constant = 5.67 × 10–8 W/m2/K4



Boltzmann’s constant (K) = 1.381 × 10-23 JK-1



One atmosphere = 76 cm Hg = 1.013 × 105 Pa



Mechanical equivalent of heat (J) = 4.186 J/cal



Planck’s constant (h) = 6.626 × 10-34 Js



Universal gas constant (R) = 8.314 J/mol–K



Permeability of free space = 4π × 10-7 Hm-1 Page | 20



Permittivity of free space = 8.854 × 10-12 Fm-1



The density of air at S.T.P. = 1.293 kg m-3



Universal gravitational constant = 6.67 × 10-11 Nm2kg-2

MCQS 1. If the percentage of A, B and C are a, b and c respectively, then the total percentage error in the product ABC is a) abc b) a + b + c c) 1/a + 1/b + 1/c d) ab + bc + ca 2. Error in the measurement of radius of sphere is 2%. Then error in the measurement of volume of sphere is a) 1% b) 5 % c) 3% d) 6 % 3. Find the error in heat loss if uncertainty in current is 2 %, resistance 1 % and time 1% (heat loss =I2 R t) a) 6% b) 4% c) 5 % d) 3 % 4. The percentage errors in the measurement of mass and speed are 2% and 3% respectively. How much will be the maximum error in kinetic energy? a) 11% b) 8% c) 5% d) 1% 5. Error in the measurement of radius of a sphere is 1%. The error in the calculated value of its volume is: a) 1% b) 3% c) 5% d) 7% 6. The percentage error in the distance 1005 cm is : a) 5 % b) 6% c) 8 % d) 20 % 7. A force F is applied on body of mass m , if error in F is 10% and in m is 5% then error in acceleration is: a) 15% b) 2% c) 1% d) 5% 8. The significant figure of the number 70034 is: a) 1 b) 4 c) 5 d) 2 9. The number of significant figures in 0.00040 m is

a) 1 b) 4 c) 5 d) 2 10. The number of significant figures in 600 m is a) 1 b) 4 c) 5 d) 2 11. The number of significant figures in 3.80 m is a) 3 b) 4 c) 5 d) 2 12. The value of 0.99 – 0.989 is a) 0.001 b) 0.010 × 10-1 -1 c) 0.01 × 10 d) 0.1 × 10-2 13. The number of significant figures in 0.007 is a) 1 b) 4 c) 5 d) 2 14. The number of significant figures in 0.080 is a) 1 b) 4 c) 5 d) 2 15. The number of significant figures in (i) 0.03800 and (ii) 90.00 is a) (i) 4 (ii) 5 b) (i) 6 (ii) 5 c) (i) 3 (ii) 6 d) (i) 4 (ii) 4 16. The number of significant figures in 3.04 × 1023 is a) 1 b) 3 c) 5 d) 2 17. The number of significant figures in 4.06×10-4 is a) 1 b) 4 c) 5 d) 3 18. The number 3498 rounded to two significant figures is a) 35 b) 3400 c) 3500 d) 4000 19. The number 3.498 rounded to two significant figures is a) 3.400 b) 3.5 c) 3.4 d) 3.500 20. The decimal equivalent of 1/20 up to three significant figures a) 0.50 b) 0.05 Page | 21

c) 0.005 d) 0.0500 21. The number of significant figures in 0.01020 is a) 3 b) 4 c) 5 d) 2 22. What is the area of a disc of radius 1.1 cm? a) 3.8 cm2 b) 3.80182 cm2

Past Papers MCQS of different Universities 1. Diopters is the unit of a) focal length b) object distance c) power of lens d) magnifying glass 2. SI unit of torque is: a) joule b) joule . second c) newton meter d) newton 3. Kilowatt-hour is the unit of: a) 3.6 × 106 joule b) 746 watt • second c) 550 ft• lb d) A.O.T 4. The quantities like mass, length, velocity, force, temperature and electric current are the examples of----a) physical quantities b) chemical quantities c) base quantities d) derived quantities 5. Who discovered decimal system: a) Indians b) Egyptians c) Arabs d) Greeks 6. Electron volt is the unit of a) power b) Torque c) Energy d) momentum 7. 1MW=_____? a) 103 W b) 106 W c) 109 W d) 1012 W 8. SI unit of velocity: a) m/s b) kg/s c) m/s2 d) m 9. 1km=-----cm. a) 103 b) 102 6 5 c) 10 d) 10 10. The dimensional formula of force is: a) [MLT] b) [LT-2] c) [MLT-2] d) [L2T-2] 11. Caloric is the unit of a) power b) Torque c) Energy d) momentum 12. Which one of the following represents the unit of acceleration? a) [MLT] b) [LT-2]

c) 3.801 cm2 d) 3.80 cm2 23. The number of significant figures in 0.900 is a) 1 b) 4 c) 5 d) 3 24. If f = x2 , then the relative error in f is a) 2 Δx/x b) (Δx/x)2 c) Δx/x d) Δx

c) [MLT-2] d) [L2T-2] 13. Which one of the following represents the dimension of the velocity? a) [MLT] b) [LT-2] -2 c) [MLT ] d) [LT-1] 14. The dimensional unit of torque is: a) [MLT] b) [LT-2] c) [M L2 T-2] d) [L2T-2] 15. Erg is the unit of energy in a) FPS b) MKS c) CGS d) SI 16. Unit of potential difference is a) volt (V) b) Ohm (Ω) c) ampere (A) d) farad (F) 17. Horse power is the unit of a) power b) Torque c) Energy d) momentum 18. The momentum of the body increase by 20% what is the % increase in its K.E a) 40 % b) 44% c) 60% d) 20% 19. Which one of the following quantities is not regarded as fundamental quantity in physics a) length b) mass c) time d) velocity 20. The unit of rate of change of momentum a) pascal (Pa) b) joule (J) c) watt (W) d) newton (N) 21. The unit of electric field intensity is a) volt / meter (V/m) b) Ohm (Ω) c) ampere (A) d) newton/meter 22. In B.T.U unit of power is Horse power and is equal to a) 746 watt b) 550 watt c) 1055 joule d) 373 watt Page | 22

23. S.I unit of angle in plane is a) radian b) steradian c) cycle d) degree 24. Unit of power of lens a) Diopters b) joule c) watt d) meter 25. S.I unit of luminous intensity is a) ampere b) mole c) kelvin d) candela 26. The S.I unit of electrical resistance a) volt (V) b) Ohm (Ω) c) ampere (A) d) farad (F) 27. The term algorithm was invented by a) Alkhuwarzimi b) Ibn e Sina c) Al Beruni d) Newton 28. 1GW=____? a) 103 W b) 106 W 9 c) 10 W d) 1012 W 29. One coulomb per sec= a) volt / meter (V/m) b) Ohm (Ω) c) ampere (A) d) newton/meter 30. [ML2T-3 ] represents the dimension of a) power b) Torque c) Energy d) momentum 31. Dimension of angular momentum are: a) [MLT] b) [LT-2] -2 c) [MLT ] d) [ML2 T-1] 32. ½ horse power = a) 746 watt b) 550 watt c) 1055 joule. d) 373 watt 33. The S.I unit of momentum is: a) N • s b) J • s c) W • s d) N/s 34. In CGS system, the fundamental units of length, mass and time respectively are: a) meter, kilogram, second b) meter, gram, second c) centimeter, gram, second

d) kilometer, kilogram, second 35. The S.I unit of magnetic induction a) weber (Web) b) Henry (H) c) Guass (G) d) Tesla (T) 36. Which of the following is the unit of pressure? a) Kg m-1s-2 b) kg m/s c) kg m2/s d) kg m2/s2 37. IBTU=_____joules a) 4.218 b) 1055 c) 746 d) 100 38. IKW=? a) 103 W b) 106 W 9 c) 10 W d) 1012 W 39. Which of the following is nit unit of electric field? a) volt (V) b) Ohm (Ω) c) ampere (A) d) newton/coulomb 40. Derived quantity among the following is a) mass b) length c) time d) density 41. Dimension of G are a) [MLT] b) [LT-2] -2 c) [MLT ] d) [M-1 L3 T-2] 42. Identity the pair whose dimension are same a) work, torque b) power, work c) momentum, force d) force, energy 43. Kilogram×meter/sec2 =---a) watt b) joule c) pascal d) newton 44. Dimension tells a) nature of physical quantity b) power of physical quantity c) nature of derived quantities d) A.O.T 45. Dimension of angular momentum a) [MLT] b) [LT-2] c) [ML2 T-1] d) [M-1 L3 T-2]

1. A second is defined as the duration of vibration of a) Carbon atom b) Cesium atom c) Radium atom d) Nitrogen atom 2. The dimension of the following is not the same a) work & energy

b) momentum & impulse c) work & torque d) Mass & weight 3. Al-Beruni determined a) Area of the moon b) Circumference of earth c) Modern electronics Page | 23

d) Radioactivity 4. Which of the following is not dimensionally correct? a) E = mv2 b) Vf = Vi + at c) s = vt2 d) s = ½ at2 5. Meter is defined as the distance traveled by light in vacuum in: a) 1 second b) 299792458 second c) 1/299792458 second d) 165076373 second 6. Which of the following is not the unit of torque: a) joule b) N • m c) kg • m2 • s-2 d) N.O.T 7. If the dimensions of a physical quantity are given [La MbTc], then the physical quantity will not be a) Force, if a=1, b=1, c=-2 b) pressure, if a=-1, b=1 c=-2 c) stress if a=-1, b=0, c=-2 d) acceleration, lf a=1, b=0, c=-2 8. The physical quantity denoted by

mass ×Gravitational Constant × density

a) force b) intensity of sound c) angular momentum d) elastic constant 9. The density of wood is 0.5 g/cm3 in cgs system of units. The corresponding value in SI units is a) 5000 b) 500 c) 50000 d) 300 10. A pressure of 106 dyne/cm2 is equivalent to a) 105 N/m2 b) 103 N/m2 7 2 c) 10 N/m d) 10-5 N/m2 11. Which the following has unit but no dimension a) Angula displacement b) length c) strain d) coefficient of friction 12. The velocity of a body is 10 mm/ns it is also a) 3.6 × 103 km/h (b) 3.6 × 107 km/h (c) 3.6 km/h (d) 3.6 × 105 km/h 13. Density of liquid is 15.7 g/cm3. Its value in the S.I system is a) 15.7 kg/m3 (b) 157 kg/m3 3 (c) 1570 kg/m (d) 15700 kg/m3 14. The velocity of a body is 36 km/h. it is also a) 10 m/s b) 20 m/s

c) 1.5 m/s d) 12 m/s 15. Which of the following is not the name of a physical quantity? a) kilogram b) force c) work d) length 16. which of the following is not unit of energy? a) W s b) kg m/s c) N m d) joule 17. Which of the following has not been expressed in suitable units? a) Stress/strain = N/m b) work = N.m c) momentum = N.s d) Torque = N.m 18. Which of the following does not have N/m2 as the unit? a) Strain b) stress c) pressure d) bulk modulus 19. If P is the pressure of a gas and V is the volume, in what unit could the quantity PV be measured? a) watt b) N s c) N m-1 d) joule 20. If p is the momentum of an object of a mass m, then the expression

p2 m

has the dimension

of a) power b) energy c) force d) impulse 21. Which of the following dimensionless? a) c) 22.

v2 rg v2 g r

The

√

Energy Mass

b)

v2 r g

d)

v2 r g

dimensional

formula

is

of

is same as that of

a) mass b) length c) time d) velocity 23. J m-1 is the unit for a) momentum b) power c) force d) N.O.T 24. The angular frequency is measured in rad s-1. Its dimension in length is a) -2 b) -1 c) 0 d) 2 25. the ratio of SI unit to CGS unit of force is a) 103 b) 105 Page | 24

c) 104

26.

a) 107 c) 10-7

d) 10-3

The ratio of 1J to 1 erg is b) 105 d) 10-5

27. If 1 kg m2 s-2 = X g cm2 s-2, what is the value of X? a) 107 b) 105 -7 c) 10 d) 10-5 28. Which of the following has no unit and no dimension a) Refractive index b) radius c) angular displacement d) sin θ 29. Which of the following is a smallest value?

a) 1mm × 1nm b) 1cm × 1km b) 1Gm × 1Km d) 1nm × 1m 30. Which of the following is the smallest one in magnitude? (a) one meter (b) one millimeter (c) one micrometer (d) one angstron 31.

1 km 1 Gm

=

a) 10-6 b) 10-3 6 c) 10 d) 103 32. Identity the pair whose dimension are same a) work, torque b) power, work c) momentum, force d) force, energy

Page | 25

KEYS MCQS – 1 1 2 3 4 5 6 7 8 9 10 B B A C A B A A C D MCQS – 2 1 D 19 C

2 C 20 B

3 A 21 B

4 B 22 C

5 A 23 D

6 C 24 C

7 B 25 A

8 C 26 B

9 A 27 A

10 D 28 A

11 D 29 B

12 D 30 C

13 C 31 C

14 D 32 A

15 C 33 C

16 B 34 A

17 C 35 A

18 C 36 D

4 B

5 A

6 B

7 C

8 D

9 C

10 11 12 13 14 15 16 17 18 D A C C A A B C D

4 A 26 B 48 D

5 B 27 D 49 B

6 D 28 C 50 D

7 A 29 A 51 C

8 A 30 D 52 A

9 B 31 D 53 B

10 C 32 D 54 C

11 D 33 D 55 C

12 A 34 B 56 A

13 D 35 B 57 D

14 B 36 A 58 C

15 A 37 A 59 C

16 B 38 B 60 A

17 B 39 D 61 A

18 C 40 A 62 B

19 B 41 C 63 C

20 A 42 D 64 B

21 C 43 C 65 D

22 A 44 C 66 D

4 D 26 D 48 D

5 C 27 B 49 C

6 A 28 B 50 A

7 A 29 A 51 D

8 B 30 C 52 C

9 B 31 D 53 C

10 D 32 D 54 D

11 B 33 A 55 D

12 B 34 D 56 D

13 B 35 D 57 C

14 C 36 D 58 C

15 C 37 D 59 B

16 C 38 C 60 C

17 A 39 C 61 D

18 D 40 D 62 C

19 C 41 A 63 D

20 C 42 C 64 B

21 D 43 C 65 D

22 D 44 A 66 C

4 B 16 B

5 B 17 D

6 A 18 C

7 A 19 B

8 C 20 D

9 B 21 B

10 A 22 A

11 A 23 D

12 B 24 A

MCQS – 3 1 B

2 C

3 D

MCQS - 4 1 B 23 C 45 D

2 C 24 B 46 B

3 C 25 D 47 D

MCQS - 5 1 C 23 C 45 A

2 C 24 C 46 B

3 A 25 B 47 C

MCQS - 6 1 B 13 A

2 C 14 D

3 A 15 D

MCQS – Past papers

1 C 23 A

2 C 24 A

3 D 25 D

4 A 26 B

5 A 27 A

6 C 28 C

7 B 29 C

8 A 30 A

9 D 31 D

10 C 32 D

11 C 33 A

12 B 34 C

13 D 35 D

14 C 36 A

15 C 37 B

16 A 38 A

17 A 39 D

18 B 40 D

19 D 41 D

20 D 42 A

21 A 43 D

22 A 44 A