Physics dimensions notes

Few sets of physical quantities having identical dimensions
i. Acceleration, gravitational field strength and acceleration due to gravity have same dimensions M°LT-2
ii. Linear momentum and impulse have identical dimensions MLT-1
iii. Work, energy, torque, couple, moment, internal energy, heat, light, work function have same dimensions ML2T-2
iv. Angular velocity, frequency, velocity gradient, radioactive decay constant and Hubble's constant have identical dimensions M°L°T-1
v. Force, thrust, weight, tension, energy gradient have same dimensions MLT-2
vi. Surface tension, force constant, spring constant, force gradient, surface energy have identical dimensions ML°T-2
vii. Pressure, stress, modulus of elasticity, energy density have identical dimensions ML-1T-2
viii. Intensity of radiation, solar constant have identical dimensions ML°T-3
ix. Gravitational potential, specific latent heat have identical dimensions M°L2T-2
x. Thermal capacity, Boltzmann's constant and entropy have same dimensions ML2T-2K-1
xi. Electric potential, electromotive force, electric potential difference have identical dimensions ML2T-3A-1
xii. Specific heat and principal gas constant have identical dimensions M°L2T-2K-1
xiii. Universal gas constant, molar specific heat capacity have identical dimensions
ML2T-2K-1 mol-1
xiv. Angular momentum and Planck's constant have same dimensions ML2T-1
xv. Magnetising force and intensity of magnetisation have identical dimensions M°L-1T°A
xvi. Rydberg's constant and wave number have identical dimensions M°L-1T°
xvii. If C, R and L are capacitance, resistance and inductance, then [C R], [L/R], [LC] have same dimensions M°L°T as time
xviii. 1oo , /k, Y/ρ , T/m , E/B, have same dimensions M°LT-1 as speed
xix. Li2, h, CV2, qV, q2/C, iVt, i2Rt, V2 R t, nRT, 1/2 I2, mgh, GMmr , 1/2mv2 have same dimensions ML2T-2 as energy
xx. Bil, BqV, Ke, I/t = impulsetime have same dimensions MLT-2 as force.
xxi. Fv, I2R, IV, V2/R have same dimensions ML2T-3 as power.

FSc ICS Notes Entry Test Exam Solution MCAT ECAT Physics First Year Chapter 11 Heat and Thermodynamics

Both Bold and Underlined option is correct

1. The centigrade and Fahrenheit scales will have the same reading when the temperature is:

• 70
• -80
• -40
• 120

2. The Fahrenheit and kelvin scale will have the same reading when the temperature is:

• 370
• 574.25
• 414.5
• 388

3. Fahrenheit scale was originally used in:

• Meteorology
• Clinical thermometer
• Clinical thermometer and meteorology
• None of these

4. A gas which strictly obeys the gas laws under all conditions of temperature and pressure is called:

• Real gas
• Ideal gas
• Inert gas
• None of these

5. The motion of molecules in gases is:

• Orderly
• Random
• Circular
• All of these

6. At constant temperature, if the density of the gas is increased, its pressure will:

• Decrease
• Increase
• Remains unchanged
• None of these

7. If a molecule will momentum mv strikes a wall and rebound then the change in momentum will be:

• -2mv
• Zero
• 2mv
• mv

8. Given that P=10(4) N/m2, area of the piston = 0.1 m(2) and distance moved by the piston = 10(-1) cm, then the work done by the gas is:

• 1J
• 10(5)J
• 10(4)J
• 10J

9. If Cv denotes molar specific heat at constant volume and ?T is the change in the temperature, then Cv∆T gives:

• Volume
• Pressure
• Energy
• Entropy

10. If temperature of the sink is decreased, efficiency of a Carnot engine:

• Remains constant
• Decreases
• Increases
• None of these

11. One degree of thermodynamic scale is equal to ________ of the temperature triple point of water.

• 1/273 th
• 1/100 th
• 1/273.16 th
• 1/32 th

12. The unknown temperature T on thermodynamic scale in kelvin is given by the formula:

• T = 273.16Q/Q3
• T = 32Q/Q3
• T = 100Q/Q3
• T = 273Q/Q3

13. A certain engine converts 20% of available heat into work. Then its efficiency will be:

• 20%
• 80%
• 50%
• None of these

14. Number of spark plugs needed in diesel engine is:

• Four
• Five
• Six
• None of these

15. Most motorbikes have ________ cylinder/s engine but cars usually have cylinders on the same crankshaft.

• Four, six
• One, four
• Two, five
• None of these

16. A constant volume gas thermometer works on:

• Archimedes principle
• Pascal's law
• Boyle's law
• Charles law

17. The ratio of coefficients of cubical expansion and linear expansion is:

• 1:1
• 3:1
• 2:1
• None of these

18. When a copper ball is heated, the largest percentage in crease will occur in its:

• Diameter
• Area
• Volume
• Density

19. Sea animals are safe in winter in cold countries because of:

• Their body conditions
• High specific heat of water
• Low conductivity of water
• Anomalous expansion of water

20. The volume expansion coefficient is:

• Equal to temperature
• Proportional to square root of temperature
• Inversely proportional to square root of temperature
• Inversely proportional to temperature

21. Heat is transferred most rapidly by the process of:

• Conduction
• Convection
• Radiation
• Combustion

22. When water is heated from 0 degree to 10 degree Celsius, its volume:

• Increases
• Decreases
• Does not change
• Data is insufficient

23. First law of thermodynamic concerns conservation of:

• Heat
• Work
• Momentum
• Energy

24. When 110J of heat is added to a gaseous system, internal energy increases by 40J; the amount of work done is:

• 150J
• 70J
• 110J
• 40J

25. Molar specific heat at constant volume Cv for a mono-atomic gas is:

• 3/2 R
• 5/2 R
• 6/2 R
• 4/2 R

26. A sink, that is a system where heat is rejected, is essential for the conservation of heat into work. From which law the above inference follows?

• Zeroth
• First
• Second
• Third

27. The first operation involved in a Carnot cycle is:

• Isothermal expansion
• Adiabatic expansion
• Isothermal compression
• Adiabatic compression

28. An ideal heat engine exhausting heat at 77 degree Celsius is to have a 30% efficiency. It must take heat at:

• 127 degree Celsius
• 227 degree Celsius
• 327 degree Celsius
• 673 degree Celsius

29. The work done in an adiabatic change in a particular gas depends upon only:

• Change in volume
• Change in pressure
• Change in temperature
• None of these

30. The gas law Constant = PV/T is true for:

• Isothermal changes only
• Adiabatic changes only
• Both isothermal and adiabatic changes
• Neither for isothermal nor for adiabatic changes

31. The physical quantity which described the level of thermal energy in a body is:

• Temperature
• Heat energy
• Pressure
• Volume

32. The pressure exerted by the gas is directly proportional to:

• Velocity of the molecule
• Density of the gas
• Square of the density
• Square root of the density

33. For an ideal gas system, the internal energy is directly proportional to:

• Pressure
• Volume
• Density
• Temperature

34. The change in internal energy of the system is positive, when the temperature of the system:

• Increases
• Decreases
• Remains constant
• None of the above

35. Water boils at 100 degree Celsius, the corresponding temperature at Fahrenheit scale is:

• 180 Fahrenheit
• 200 Fahrenheit
• 212 Fahrenheit
• 273 Fahrenheit

36. A Celsius degree is larger than a Fahrenheit degree by:

• 5/9
• 9/5
• 9/10
• 9/8

37. Absolute zero is considered as that temperature at which:

• All liquids become gases
• All gases become liquids
• Water freezes
• All gases partially liquefied

38. At constant volume, the graph between P and T is:

• Hyperbola
• Parabola
• Straight line
• Ellipse

39. At constant temperature, if the pressure of the given mass of the gas is doubled, then the density of the gas becomes:

• Double
• 1/4 of the original value
• 1/2 of the original value
• Remains constant

40. An inflated tire suddenly bursts. As a result of this, the temperature of air:

• Increases
• Decreases
• May increase or decrease
• Remains constant

41. When the gas expands isothermally, the work is:

• Done on the gas
• Done by the gas
• Zero
• Negative

42. The SI unit of molar specific heat is:

• Jmol/K
• J/molK
• JK/mol
• J/mol

43. The coefficient of linear expansion of platinum is 9*10(-6) per Coulomb. Its coefficient of volume expansion is:

• 3*10(-6) per Coulomb
• 9*10(-6) per Coulomb
• 18*10(-6) per Coulomb
• 27*10(-6) per Coulomb

44. The SI unit of entropy is:

• J/K
• J/s
• Js/K
• J/K(2)

45. The natural process tends to proceed towards a state of greater:

• Order
• Disorder
• Both order and disorder
• Neither order nor disorder

46. Which of the following is not the function of state?

• Internal energy
• Entropy
• Enthalpy
• Mass

47. Entropy of universe during any natural process:

• Increases
• Increases or remains constant
• Decreases
• Decreases or remains constant

48. When a sphere is heated, then the greatest increase is in its:

• Radius
• Circumference
• Surface area
• Volume

49. Net change in entropy of a system in a Carnot's cycle is:

• Positive
• Negative
• Maximum
• Zero

50. Area under the p-v graph of Carnot engine represents the:

• Heat absorbed
• Heat rejected
• Total work done
• All of the above

51. Temperature of gas is a measure of:

• the average translational kinetic energy of the gas molecule
• the average potential energy of the gas molecules
• the average distance of the gas molecules
• the size of the gas molecules

52. A thermometric liquid which can be used to measure temperature between -40 degree Celsius to 40 degree Celsius is:

• Water
• Alcohol
• Mercury
• Phenol

53. The temperature at which the reading of a Fahrenheit thermometer will be double that of Centigrade thermometer is:

• 160 degree Celsius
• 180 degree Celsius
• 32 degree Celsius
• 100 degree Celsius

54. For measuring temperature near absolute zero, the thermometer used is:

• Thermoelectric thermometer
• Radiation thermometer
• Magnetic thermometer
• Resistance thermometer

55. The absolute zero is the temperature at which:

• Water freezes
• All substances exist in solid state
• Molecular motion ceases
• None of the above

56. Absolute zero (0K) is that temperature at which:

• Matter ceases to exist
• Ice melts and water freezes
• Molecular motion ceases
• None of the above

57. The temperature on Celsius scale is 25 degree Celsius. What is the corresponding temperature on the Fahrenheit scale?

• 40 F
• 77 F
• 50 F
• 45 F

58. The root mean square speed of the molecules of different ideal gases, maintained at the same temperature are:

• Same
• Different
• Zero
• Infinity

59. 'P' is pressure and 'd' is the density of the gas at constant temperature, then:

• P ∝ 1/d
• P ∝ 1/d(2)
• P ∝ d
• P ∝ d(2)

60. The number of molecules per cc of a gas at S.T.P. is:

• 2.68*10(17)
• 2.68*10(19)
• 22400*6*10(23)
• 6*10(23)

61. In winter, the temperature of the inside wall of a room as compared to the temperature of air in the room is:

• Lower
• Higher
• Same
• May be lower or higher depending upon atmospheric pressure

62. Pressure of a gas can be written as:

• 1/3 ρV
• 1/3 V(2)
• 1/3 ρV(2)
• 1/3 ρ(2)V

63. One Kelvin is defined as:

• 1/100 of boiling point of water
• 1/273.16 of melting of ice
• 1/273.16 of boiling point of water
• 1/273.16 of temperature of triple point of water

64. The value of Boltzmann's constant is:

• 1.38*10(-23)J/K
• 1.38*10(23)J/K
• 1.38*10(-23)J/mole-K
• 1.38*10(-23)J/K mole-K

65. For a gas obeying Boyle's law if the pressure is doubled, the volume becomes:

• Double
• One half
• Three fold
• Remains the same

66. If coefficient of linear expansion of a solid is a, its coefficient of cubical expansion will be approximately:

• 2a
• 3a
• 2.5a
• 4a

67. The SI units of specific heat are:

• K cal / kg K
• Cal / gram C
• K cal / kg C
• J / kg K

68. In an adiabatic process:

• Q = ∆U + W
• Q = ∆U
• Q = W
• Q = 0

69. A system does 600 J of work and at the same time its internal energy increased by 320J. How much heat has  bee supplied?

• 280J
• 920J
• 600J
• 20J

70. No entropy change takes place in:

• Isothermal process
• Adiabatic process
• Isobaric process
• Isochoric process

FSc ICS MCAT ECAT Physics First Year Chapter 1 Measurements Multiple Choice Question(MCQ) Notes

Both Bold and Underlined option is correct

1. The branch of physics "wave mechanic"introduced by:

• Einstein
• Max Plank
• De-broglie
• Bohr

2. Physicists started believing that every thing about physics has been discovered by the end of:

• 20 th century
• 19 th century
• 15 th century
• None of these

3. Pascal is famous for his work:

• Hydrostatics
• Hydrodynamics
• Laws of gases
• Behaviour of elastic bodies

4. Systems international (SI) was established in:

• 1960
• 1967
• 1971
• 1930

5. The basic quantity among following is:

• Torque
• Force
• Mass
• Velocity

6. Which one of the scientist made some contribution to geometrical optics:

• Archimedes
• Pythagoras
• Euclid
• Plato

7. Which of the following is the derived quantity:

• Time
• Area
• Length
• Mass

8. Which of the following is set of supplementary units:

• Radian & kilogram
• Steradian & time
• Mole & radian
• Radian & steradian

9. The SI unit for measuring plane angle is:

• Radian
• Steradian
• Both first and second
• None of these

10. The present standard meter is defined as:

• The distance between  two points on an alloy bar
• The length of mean solar day
• The length equal to 1650763.73 wavelength of krypton 86-atom
• The distance travel by the light in vacuum during a time of 1/299792458 second

11. The system international (SI) built up from:

• Derived units
• Basic units
• Supplementary units
• All of these

12. One mile is equal to:

• 1.625 km
• 1.609 km
• 1.325 km
• 1.850 km

13. One inch is equal to:

• 1.32 cm
• 25.4 cm
• 2.10 cm
• 2.54 cm

14. One foot is equal to:

• 31.90 cm
• 30.84 cm
• 30.48 cm
• 84.30 cm

15. Number of nano second in a year is:

• 3.1536 * 10(7)
• 3.1536 * 10(9)
• 3.1536 * 10(16)
• None of these

16. One year is equal to:

• 3.2 * 10(7) sec
• 2.25 * 10(7) sec
• 3.35 * 10(7) sec
• All of these

17. Light year is the unit of:

• Light
• Time
• Velocity
• Distance

18. The unit of thermodynamic temperature is:

• K
• C
• F
• None of these

19. One atto is:

• 10(-20)
• 10(-16)
• 10(-14)
• 10(-18)

20. One femto is:

• 10(-16)
• 10(-12)
• 10(-15)
• 10(-9)

21. The number of significant figure in 8.80 * 10(6) kg is:

• 1
• 5
• 3
• 6

22. The number 64.350 is rounded off as:

• 64.35
• 64.46
• 64.36
• 64.4

23. In scientific notation, the number 0.01 may be written as:

• 10(-2)
• 10(-4)
• 10 * 10(-4)
• 1 * 10(-4)

24. If length = 0.233 m and width = 0.178 m, the most accurate area expressed space of significant figures is:

• 0.041 m(2)
• 0.0415 m(2)
• 0.041747 m(2)
• None of these

25. The number 0.0001 in scientific notation is:

• 1 * 10(4)
• 10(-3)
• 10 * 10(4)
• 10(-4)

26. One mega is equal to:

• 10(6)
• 10(-6)
• 10(3)
• 10(9)

27. The error in a certain measurement occurs due to:

• Negligence of a person
• Inappropriate technique
• Faulty apparatus
• All of the above

28. The uncertainty may occur due to:

• Limitation of an instrument
• Natural variance of the object
• Personal negligence
• All of the above

29. The least count of a unit meter rod is:

• 0.01 cm
• 0.01 mm
• Cannot be zero
• Can be zero

30. The number of base units in SI are:

• Four
• Five
• Six
• Seven

31. Deca, deci and mega, respectively mean:

• 10(1), 10(-1), 10(6)
• 10(6), 10(-1), 10(1)
• 10(6), 10(1), 10(-1)
• 10(1), 10(6), 10(-1)

32. 134.7 should be written in scientific notation as:

• 134.7
• 13.45 * 10(1)
• 1.347 * 10(2)
• 0.1347 * 10(3)

33. Pico, kilo and terra mean:

• 10(-12), 10(-3), 10(-18)
• 10(18), 10(3), 10(-12)
• 10(-12), 10(3), 10(12)
• 10(18), 10(-12), 10(3)

34. The average time the Earth takes to make exactly one rotation about its axis is defined as:

• A solar hour
• A solar day
• A light year
• A solar month

35. The distance x determined by the difference between two separate position measurements x1 = 10.5 +-(0.1) cm and x2 26.8 +-(0.1) cm. Then x will be recorded as:

• 16.3 cm
• 16.3 +-(0.1) cm
• 16.3 +-(0.2) cm
• 16.3 +-(0.01) cm

36. The length of a line was measured with a meter scale of least count = 1 mm by four students. The correct reading will be:

• 0.5426 m
• 0.542 m
• 0.54 m
• 0.5 m

37. Name the scientist who was awarded the Nobel Prize in physics in 1936 for the discovery of the positron:

• Chadwick
• Femi
• Anderson
• Einstein

38. The density of mercury is 13600 kg/m(3). Its value in CGS system will be:

• 13.6 g/cm(3)
• 1360 g/cm(3)
• 136 g/cm(3)
• 1.36 g/cm(3)

39. The unit of force and length are doubled, the unit of energy will be:

• 1/2 times
• 1/3 times
• 2 times
• 4 times

40. The dimensional formula [ML(0)T(-3)] is more closely associated with:

• Power
• Energy
• Intensity
• Velocity gradient

41. Which dimensions will be the same as that of time?

• LC
• R / L
• L / R
• C / L

42. Angular momentum has the same dimensions as:

• Plank's constant
• Universal gravitational constant
• Rydberg constant
• Boltzmann constant

43. Which of the two have same dimensions?

• Force and strain
• Force and stress
• Angular velocity and frequency
• Energy and strain

44. A student measured the diameter of a wire using a screw gauge with least count 0.001 cm and listed the measurements. The correct measurement is:

• 5.320 cm
• 5.3 cm
• 5.32 cm
• 5.3200 cm

45. Zero error belongs to the category of:

• Constant errors
• Personal errors
• Instrumental errors
• Accidental errors

46. Which one is the least sub-multiple?

• pico
• femto
• atto
• nano

47. In which system, the unit of force is a base unit:

• SI system
• CGS system
• British engineering system
• MKS system

48. Which of the following cannot be expressed as Nm(-2):

• Pressure
• Stress
• Surface tension
• Bulk modulus of elasticity

49. Which of the following units is used to measure the radius of nucleus?

• Micron
• Nanometer
• Angstrom
• Femtometer

50. Which of the following is not equal to watt?

• Joule / second
• Ampere * Volt
• Ampere(2) * ohm
• Ampere / volt

51. Temperature can be expressed as a derived quantity in terms of any of the following:

• Length and mass
• Mass and time
• Length, mass and time
• In terms of none of these

52. erg/m can be the unit of the measure of:

• Force
• Momentum
• Power
• Acceleration

53. IF the radius of the Earth shrinks by 1.5% (mass remaining same) then the value of acceleration due to gravity changes by:

• 1%
• 2%
• 3%
• 4%

54. Which of the following readings taken by microscope of least count 0.001 cm is correct?

• 3.28
• 3.00
• 3.000
• 0.02345

55. Which of the following is not a base unit in SI system:

• Temperature
• Amount of substance
• Light intensity
• Area

56. The minimum number of physical quantities which define other physical quantities is SI system are:

• Two
• Three
• Five
• Seven

57. Which of the following is not a unit of time:

• Leap year
• Light year
• Lunar month
• Micro second

58. Three dimensional angel subtended at the center of the sphere by an area of its surface equal to the square of radius of the sphere is called:

• Radian
• Steradian
• Degree
• All of the above

59. The ratio of 1 nanometer to 1 attometer is equal to:

• 1 peta
• 1 tera
• 1 giga
• 1 mega

60. A precise measurement is the one which has:

• Less absolute uncertainty
• Less percentage uncertainty
• Large fractional uncertainty
• Large absolute uncertainty

61. The accuracy of measurement depends on:

• Absolute uncertainty
• Percentage uncertainty
• Quality of the instrument
• Calibration of the scale

62. Number of significant figure with increasing degree of approximation:

• Decreases
• Increases
• Remains unchanged
• None of the above

63. Solid angle subtended at the center by a sphere is:

• 2 π
• 4 π
• 6 π
• 8 π

64. A second pendulum strikes in a day:

• 3600 times
• 86400 times
• 43200 times
• 0.003 sec

65. The density of wood is 0.5g/cm(3) in CGS system of units. The corresponding value in SI units is:

• 500 kg/m(3)
• 5 kg/m(3)
• 0.5 kg/m(3)
• 5000 kg/m(3)

66. Physical quantity is/are:

• Time
• Density
• Temperature
• All

67. The error is constant for _______ error.

• Random
• Systematic
• Both first and second
• All

68. For 2450 number of significant digits:

• 4
• 3
• 2
• 1

69. Which of the following could be measured in the same units as force?

• Energy / Distance
• Energy * Distance
• Energy / Time
• Momentum * Distance

70. What is the ratio 1 micrometer / 1 Giga meter

• 10(-3)
• 10(-6)
• 10(-12)
• 10(-15)