Unit and Measurement 100 MCQs With Answer and Explanation

1. The process of assigning numbers to physical quantities is called:
A) Measuring
B) Counting
C) Estimating
D) Calculating

2. The internationally accepted system of units is:
A) FPS system
B) CGS system
C) SI system
D) MKS system

3. The SI base unit of length is:
A) Foot
B) Centimeter
C) Meter
D) Kilometer

4. Which of the following is NOT a fundamental quantity?
A) Mass
B) Time
C) Velocity
D) Length

5. The SI unit of mass is:
A) Gram
B) Kilogram
C) Quintal
D) Pound

6. The SI unit of electric current is:
A) Volt
B) Coulomb
C) Ampere
D) Ohm

7. The SI unit of temperature is:
A) Celsius
B) Kelvin
C) Fahrenheit
D) Joule

8. The SI unit of luminous intensity is:
A) Lux
B) Candela
C) Watt
D) Lumen

9. The SI unit of amount of substance is:
A) Mole
B) Gram mole
C) Kilomole
D) Molecule

10. Which of the following is a derived quantity?
A) Length
B) Time
C) Force
D) Mass

11. The SI unit of force is:
A) Dyne
B) Newton
C) Joule
D) Pascal

12. The SI unit of energy is:
A) Newton
B) Joule
C) Watt
D) Calorie

13. The SI unit of pressure is:
A) Pascal
B) Newton
C) Bar
D) Torr

14. Which unit is NOT used in the SI system?
A) Meter
B) Kilogram
C) Second
D) Foot

15. The dimensional formula of velocity is:
A) [M¹L¹T⁻²]
B) [M⁰L¹T⁻¹]
C) [M¹L⁰T⁻¹]
D) [M⁰L¹T⁻²]

16. Which of these is NOT a base unit in SI?
A) Second
B) Candela
C) Joule
D) Meter

17. In physics, a unit is defined as:
A) A standard measure of quantity
B) A large number
C) A mathematical constant
D) None of these

18. The SI unit of frequency is:
A) Hertz
B) Joule
C) Watt
D) Decibel

19. The SI unit of power is:
A) Watt
B) Volt
C) Joule
D) Newton

20. The SI unit of work is:
A) Joule
B) Newton
C) Watt
D) Erg

21. The dimensional formula of acceleration is:
A) [M⁰L¹T⁻²]
B) [M⁰L¹T⁻¹]
C) [M¹L¹T⁻²]
D) [M⁰L⁰T⁻²]

22. The dimensional formula of force is:
A) [M¹L¹T⁻²]
B) [M⁰L¹T⁻²]
C) [M¹L⁰T⁻²]
D) [M¹L²T⁻²]

23. The dimensional formula of energy is:
A) [M¹L¹T⁻²]
B) [M¹L²T⁻²]
C) [M⁰L²T⁻²]
D) [M¹L²T⁰]

24. Which one of these is dimensionless?
A) Strain
B) Velocity
C) Energy
D) Momentum

25. The dimensional formula of pressure is:
A) [M¹L⁻¹T⁻²]
B) [M¹L¹T⁻²]
C) [M⁰L⁻¹T⁻²]
D) [M¹L²T⁻²]

26. The dimensional formula of gravitational constant (G) is:
A) [M⁻¹L³T⁻²]
B) [M¹L³T⁻²]
C) [M⁻¹L²T⁻²]
D) [M⁰L³T⁻²]

27. The dimensional formula of momentum is:
A) [M¹L¹T⁻¹]
B) [M¹L¹T⁻²]
C) [M⁰L¹T⁻¹]
D) [M¹L²T⁻²]

28. Which of the following pairs have the same dimensions?
A) Work and Torque
B) Power and Energy
C) Force and Energy
D) Pressure and Energy

29. The dimensional formula of Planck’s constant (h) is:
A) [M¹L²T⁻¹]
B) [M¹L²T⁻²]
C) [M⁰L²T⁻²]
D) [M¹L²T⁰]

30. Which one of the following is NOT dimensionless?
A) Refractive index
B) Poisson’s ratio
C) Angular displacement (in radians)
D) Electric charge

31. The dimensional formula of velocity is:
A) [M⁰L¹T⁻¹]
B) [M¹L¹T⁻²]
C) [M⁰L¹T⁰]
D) [M⁰L¹T⁻²]

32. Which has the same dimensions as impulse?
A) Force
B) Momentum
C) Power
D) Energy

33. Which of the following is a correct equation dimensionally?
A) v = u + at
B) v² = u² + 2as
C) s = ut + ½at²
D) All of these

34. The dimensional formula of universal gas constant (R) is:
A) [M¹L²T⁻²K⁻¹mol⁻¹]
B) [M¹L²T⁻²]
C) [M¹L²T⁻²mol⁻¹]
D) [M¹L²T⁻²K⁻¹]

35. Which of the following has dimensions of energy?
A) Torque
B) Work
C) Potential energy
D) All of these

36. Which is NOT a use of dimensional analysis?
A) Checking correctness of equations
B) Finding units of quantities
C) Determining exact numerical constants
D) Converting units

37. The dimensional formula of surface tension is:
A) [M¹L⁰T⁻²]
B) [M¹L⁻¹T⁻²]
C) [M¹L¹T⁻²]
D) [M⁰L⁻¹T⁻²]

38. The dimensional formula of angular momentum is:
A) [M¹L²T⁻¹]
B) [M¹L²T⁻²]
C) [M¹L¹T⁻¹]
D) [M⁰L²T⁻¹]

39. The dimensions of Planck’s constant divided by speed of light are:
A) [M¹L¹T⁻¹]
B) [M¹L¹T⁰]
C) [M¹L⁰T⁻¹]
D) [M⁰L¹T⁻¹]

40. Dimensional analysis fails in case of:
A) Addition of quantities
B) Trigonometric functions
C) Logarithmic functions
D) All of these

41. The SI unit of electric current is:
A) Coulomb
B) Volt
C) Ampere
D) Ohm

42. Which of these is not a base quantity in the SI system?
A) Length
B) Time
C) Mass
D) Velocity

43. The dimension of pressure is:
A) [MLT⁻²]
B) [ML⁻¹T⁻²]
C) [ML²T⁻²]
D) [M⁰L⁰T⁰]

44. Which method is used to check the dimensional correctness of an equation?
A) Dimensional analysis
B) Unit conversion
C) Significant figures
D) None of these

45. The SI unit of luminous intensity is:
A) Lux
B) Candela
C) Lumen
D) Watt

46. One light year is a unit of:
A) Time
B) Distance
C) Speed
D) Energy

47. Which of the following pairs is correct?
A) Frequency – Hertz
B) Force – Joule
C) Energy – Watt
D) Pressure – Newton

48. The SI unit of angular velocity is:
A) rad/s
B) rad/s²
C) Hz
D) m/s

49. The number of base units in the SI system is:
A) 5
B) 7
C) 9
D) 6

50. The dimension of energy is:
A) [MLT⁻²]
B) [ML²T⁻²]
C) [ML²T⁻³]
D) [M⁰L⁰T⁰]

51. The SI unit of work is:
A) Watt
B) Newton
C) Joule
D) Pascal

52. The dimension of power is:
A) [ML²T⁻³]
B) [MLT⁻²]
C) [ML²T⁻²]
D) [M⁰L⁰T⁰]

53. The SI unit of surface tension is:
A) N/m²
B) N/m
C) Pa
D) m²/N

54. Which of the following is a dimensionless quantity?
A) Strain
B) Stress
C) Pressure
D) Velocity

55. The SI unit of gravitational constant (G) is:
A) m³kg⁻¹s⁻²
B) m²kg⁻²s⁻²
C) m³kg⁻²s⁻¹
D) m²kg⁻¹s⁻²

56. Which physical quantity has dimensions [ML⁻¹T⁻²]?
A) Pressure
B) Energy
C) Velocity
D) Power

57. The SI unit of electric charge is:
A) Volt
B) Coulomb
C) Ohm
D) Ampere

58. Which of these is NOT a derived unit?
A) Joule
B) Meter
C) Watt
D) Pascal

59. The dimension of universal gas constant R is:
A) [ML²T⁻²K⁻¹mol⁻¹]
B) [MLT⁻²K⁻¹mol⁻¹]
C) [M⁰L⁰T⁰K⁻¹mol⁻¹]
D) [ML²T⁻³K⁻¹mol⁻¹]

60. The SI unit of luminous flux is:
A) Lumen
B) Lux
C) Candela
D) Watt

61. 1 angstrom (Å) equals:
A) 10⁻⁸ m
B) 10⁻¹⁰ m
C) 10⁻⁹ m
D) 10⁻¹² m

62. The dimension of Planck’s constant (h) is:
A) [ML²T⁻¹]
B) [ML²T⁻²]
C) [ML²T⁻³]
D) [MLT⁻¹]

63. Which is the correct SI unit for frequency?
A) rad/s
B) cycles/s
C) Hz
D) All of these

64. Which has no physical dimension?
A) Refractive index
B) Energy
C) Momentum
D) Force

65. The SI unit of momentum is:
A) kg·m/s
B) N·s
C) Both A and B
D) Joule

66. Which of these is NOT an SI base unit?
A) Kelvin
B) Mole
C) Litre
D) Candela

67. The dimensional formula of velocity is:
A) [MLT⁻²]
B) [MLT⁻¹]
C) [M⁰LT⁻¹]
D) [ML²T⁻²]

68. 1 micron equals:
A) 10⁻⁴ m
B) 10⁻⁶ m
C) 10⁻⁸ m
D) 10⁻⁹ m

69. The SI unit of pressure is:
A) Pa
B) N/m²
C) kg·m⁻¹·s⁻²
D) All of these

70. Which is a vector quantity?
A) Speed
B) Work
C) Power
D) Velocity

71. The SI unit of magnetic flux is:
A) Weber
B) Tesla
C) Henry
D) Ohm

72. The dimension of force constant (spring constant) is:
A) [MT⁻²]
B) [MLT⁻²]
C) [MT⁻¹]
D) [ML⁻¹T⁻²]

73. Which unit is used for measuring astronomical distances?
A) Light year
B) Parsec
C) Astronomical unit
D) All of these

74. The SI unit of capacitance is:
A) Farad
B) Ohm
C) Coulomb
D) Henry

75. The dimensional formula of torque is:
A) [ML²T⁻²]
B) [MLT⁻²]
C) [ML²T⁻³]
D) [M²L²T⁻²]

76. Which physical quantity has unit Tesla?
A) Magnetic flux
B) Magnetic field
C) Magnetic moment
D) Current density

77. The SI unit of resistivity is:
A) Ohm·m
B) Ohm/m
C) Ohm/m²
D) Ohm⁻¹·m

78. The dimensional formula of electric potential difference is:
A) [ML²T⁻³A⁻¹]
B) [ML²T⁻²A⁻¹]
C) [MLT⁻³A⁻¹]
D) [ML²T⁻¹A⁻¹]

79. Which unit is used for luminous intensity?
A) Lumen
B) Lux
C) Candela
D) Watt

80. 1 femtometer equals:
A) 10⁻¹² m
B) 10⁻¹⁵ m
C) 10⁻⁹ m
D) 10⁻¹⁰ m

81. The SI unit of inductance is:
A) Henry
B) Weber
C) Ohm
D) Tesla

82. The dimensional formula of impulse is:
A) [ML²T⁻²]
B) [MLT⁻²]
C) [MLT⁻¹]
D) [MLT⁻¹]

83. Which is a fundamental physical constant?
A) G
B) h
C) c
D) All of these

84. The SI unit of entropy is:
A) J/K
B) J/mol
C) J/mol·K
D) W/K

85. The dimensional formula of density is:
A) [ML⁻³]
B) [MLT⁻²]
C) [M⁰LT⁻³]
D) [ML²T⁻²]

86. Which unit measures frequency of a wave?
A) Watt
B) Hertz
C) Joule
D) Pascal

87. The SI unit of angular acceleration is:
A) rad/s²
B) rad/s
C) m/s²
D) m/s

88. Which is a scalar quantity?
A) Velocity
B) Acceleration
C) Force
D) Speed

89. The dimensional formula of modulus of elasticity is same as:
A) Energy
B) Pressure
C) Force
D) Work

90. Which of these is NOT an SI derived unit?
A) Pascal
B) Joule
C) Watt
D) Degree Celsius

91. The SI unit of heat is:
A) Joule
B) Calorie
C) Watt
D) Kelvin

92. 1 electronvolt (eV) equals:
A) 1.6 × 10⁻¹⁹ J
B) 3.0 × 10⁸ J
C) 9.1 × 10⁻³¹ J
D) 1.6 × 10¹⁹ J

93. The SI unit of specific heat capacity is:
A) J/kg·K
B) J/mol·K
C) J/K
D) Calorie

94. Which quantity has dimension [ML²T⁻²]?
A) Energy
B) Power
C) Momentum
D) Pressure

95. The SI unit of kinematic viscosity is:
A) m²/s
B) m/s²
C) m/s
D) m³/s

96. The SI unit of permeability is:
A) H/m
B) Wb/m
C) T·m/A
D) Ω·m

97. Which physical quantity has unit Newton-second?
A) Impulse
B) Momentum
C) Both A and B
D) Power

98. The dimensional formula of acceleration is:
A) [MLT⁻²]
B) [M⁰LT⁻²]
C) [ML²T⁻³]
D) [M⁰LT⁻¹]

99. The SI unit of thermal conductivity is:
A) W/m·K
B) W/m²·K
C) W·K/m
D) W/K

100. Which is the base unit for thermodynamic temperature?
A) Celsius
B) Kelvin
C) Fahrenheit
D) Rankine