Tiêu đề 01. Units and Dimensions Easy[Vijaya].pdf ✅

02. UNITS and DIMENSIONS [ Easy] 1. Light year is a unit of (a) Time (b) Mass (c) Distance (d) Energy 2. The magnitude of any physical quantity (a) Depends on the method of measurement (b) Does not depend on the method of measurement (c) Is more in SI system than in CGS system (d) Directly proportional to the fundamental units of mass, length and time 3. Which of the following is not equal to watt (a) Joule/second (b) Ampere  volt (c) (Ampere)2  ohm (d) Ampere/volt 4. Newton–second is the unit of (a) Velocity (b) Angular momentum (c) Momentum (d) Energy 5. Which of the following is not represented in correct unit (a) 2 / Strain Stress = N m (b) Surface tension = N/m (c) Energy = kg-m/sec (d) Pressure 2 = N/m 6. One second is equal to (a) 1650763.73 time periods of Kr clock (b) 652189.63 time periods of Kr clock (c) 1650763.73 time periods of Cs clock (d) 9192631770 time periods of Cs clock 7. One nanometre is equal to (a) mm 9 10 (b) cm 6 10 − (c) cm 7 10 − (d) cm 9 10 − 8. A micron is related to centimetre as (a) micron cm 8 1 10 − = (b) micron cm 6 1 10 − = (c) micron cm 5 1 10 − = (d) micron cm 4 1 10 − = 9. The unit of power is (a) Joule (b)Joule per second only (c) Joule per second and watt both (d) Only watt 10. A suitable unit for gravitational constant is (a) 1 - sec− kg m (b) sec −1 N m (c) 2 −2 N m kg (d) 1 sec− kgm 11. SI unit of pressure is (a) Pascal (b) 2 Dynes / cm (c) cm of Hg (d) Atmosphere 12. The unit of angular acceleration in the SI system is (a) −1 N kg (b) −2 m s (c) −2 rad s (d) m kg K −1 13. The unit of Stefan's constant  is (a) −2 −1 W m K (b) 2 −4 W m K (c) −2 −4 W m K (d) 2 4 W m K − 14. Which of the following is not a unit of energy (a) W- s (b) kg - m /sec (c) N- m (d) Joule 15. In 2 S = a + bt + ct . S is measured in metres and t in seconds. The unit of c is (a) None (b) m (c) −1 ms (d) −2 ms 16. Joule-second is the unit of (a) Work (b) Momentum (c) Pressure (d) Angular momentum 17. Unit of energy in SI system is (a) Erg (b) Calorie (c) Joule (d) Electron volt
18. A cube has numerically equal volume and surface area. The volume of such a cube is (a) 216 units (b) 1000 units (c) 2000 units (d) 3000 units 19. Wavelength of ray of light is 0.00006 m . It is equal to (a) 6 microns (b) 60 microns (c) 600 microns (d) 0.6 microns 20. Electron volt is a unit of (a) Charge (b) Potential difference (c) Momentum (d) Energy 21. Temperature can be expressed as a derived quantity in terms of any of the following (a) Length and mass (b) Mass and time (c) Length, mass and time (d) None of these 22. Unit of power is (a) Kilowatt (b) Kilowatt-hour (c) Dyne (d) Joule 23. Density of wood is 0.5gm / cc in the CGS system of units. The corresponding value in MKS units is (a) 500 (b) 5 (c) 0.5 (d) 5000 24. Unit of energy is (a) J / sec (b) Watt − day (c) Kilowatt (d) 2 gm-cm /sec 25. Which is the correct unit for measuring nuclear radii (a) Micron (b) Millimetre (c) Angstrom (d) Fermi 26. One Mach number is equal to (a) Velocity of light (b) Velocity of sound (332 m / sec) (c) 1 km /sec (d) 1m / sec 27. The unit for nuclear dose given to a patient is (a) Fermi (b) Rutherford (c) Curie (d) Roentgen 28. Volt/metre is the unit of (a) Potential (b) Work (c) Force (d) Electric intensity 29. 2 Newton/metre is the unit of (a) Energy (b) Momentum (c) Force (d) Pressure 30. The unit of surface tension in SI system is (a) 2 Dyne / cm (b) Newton / m (c) Dyne / cm (d) 2 Newton / m 31. The unit of reduction factor of tangent galvanometer is (a) Ampere (b) Gauss (c) Radian (d) None of these 32. The unit of self inductance of a coil is (a) Farad (b) Henry (c) Weber (d) Tesla 33. Henry/ohm can be expressed in (a) Second (b) Coulomb (c) Mho (d) Metre 34. The SI unit of momentum is (a) m kg (b) sec kg.m (c) sec . 2 kg m (d) kg  Newton 35. The velocity of a particle depends upon as 2 v = a + bt + ct ; if the velocity is in m / sec , the unit of a will be (a) m /sec (b) 2 m /sec (c) / sec 2 m (b) 3 m / sec 36. One million electron volt (1 MeV) is equal to (a) eV 5 10 (b) eV 6 10 (c) eV 4 10 (d) eV 7 10 37. −1 Erg − m can be the unit of measure for (a) Force (b) Momentum (c) Power (d) Acceleration 38. The unit of potential energy is (a) ( / sec ) 2 g cm (b) 2 g(cm / sec) (c) ( / sec) 2 g cm (d) g(cm / sec) 39. Which of the following represents a volt (a) Joule/second (b) Watt/Ampere (c) Watt/Coulomb (d) Coulomb/Joule 40. Kilowatt− hour is a unit of (a) Electrical charge (b) Energy (c) Power (d) Force 41. What is the SI unit of permeability (a) Henry per metre (b)Tesla metre per ampere (c) Weber per ampere metre (d)All the above units are correct
42. In which of the following systems of unit, Weber is the unit of magnetic flux (a) CGS (b) MKS (c) SI (d) None of these 43. If the unit of length and force be increased four times, then the unit of energy is (a) Increased 4 times (b) Increased 8 times (c) Increased 16 times (d) Decreased 16 times 44. Oersted is a unit of (a) Dip (b) Magnetic intensity (c) Magnetic moment (d) Pole strength 45. Ampere − hour is a unit of (a) Quantity of electricity (b) Strength of electric current (c) Power (d) Energy 46. The unit of specific resistance is (a) 2 Ohm/cm (b) Ohm/cm (c) Ohm−cm (d) 1 ( ) − Ohm−cm 47. The binding energy of a nucleon in a nucleus is of the order of a few (a) eV (b) Ergs (c) MeV (d) Volts 48. Parsec is a unit of (a) Distance (b) Velocity (c) Time (d) Angle 49. If 1 u and 2 u are the units selected in two systems of measurement and 1 n and 2 n their numerical values, then (a) n1u1 = n2u2 (b) n1u1 + n2u2 = 0 (c) n1n2 = u1u2 (d) ( ) ( ) n1 + u1 = n2 + u2 50. 1 eV is (a) Same as one joule (b) J 19 1.6 10 −  (c) 1V (d) C 19 1.6 10 −  51. 1kWh = (a) 1000 W (b) J 5 36 10 (c) 1000 J (d) 3600 J 52. Universal time is based on (a) Rotation of the earth on its axis (b)Earth's orbital motion around the earth (c) Vibrations of cesium atom (d)Oscillations of quartz crystal 53. The nuclear cross-section is measured in barn, it is equal to (a) 20 2 10 m − (b) 30 2 10 m − (c) 28 2 10 m − (d) 14 2 10 m − 54. Unit of moment of inertia in MKS system (a) 2 kg cm (b) 2 kg/cm (c) 2 kgm (d) Joulem 55. Unit of stress is (a) N/m (b) N−m (c) 2 N/m (d) 2 N−m 56. Unit of Stefan's constant is (a) −1 J s (b) −2 −1 −4 J m s K (c) −2 J m (d) J s 57. Unit of magnetic moment is (a) 2 Ampere−metre (b) Ampere −metre (c) 2 Weber−metre (c) Weber/metre 58. Curie is a unit of (a) Energy of -rays (b) Half life (c) Radioactivity (d) Intensity of -rays 59. Hertz is the unit for (a) Frequency (b) Force (c) Electric charge (d) Magnetic flux 60. One pico Farad is equal to (a) F 24 10 − (b) F 18 10 − (c) F 12 10 − (d) F 6 10 − 61. In SI, Henry is the unit of (a) Self inductance (b) Mutual inductance (c) (a) and (b) both (d) None of the above 62. The unit of e.m.f. is (a) Joule (b) Joule-Coulomb (c) Volt–Coulomb (d) Joule/Coulomb 63. Which of the following is not the unit of time (a) Micro second (b) Leap year (c) Lunar months (d) Parallactic second 64. Unit of self inductance is (a) Coulomb Ampere Newton - second  (b) Ampere Joule/Coulomb  Second (c) Coulomb Voltmetre (d) Ampere Newton metre
65. To determine the Young's modulus of a wire, the formula is ; L L A F Y  =  where L = length, A = area of cross-section of the wire, L = change in length of the wire when stretched with a force F . The conversion factor to change it from CGS to MKS system is (a) 1 (b) 10 (c) 0.1 (d) 0.01 66. Young's modulus of a material has the same units as (a) Pressure (b) Strain (c) Compressibility (d) Force 67. One yard in SI units is equal (a) 1.9144 metre (b) 0.9144 metre (c) 0.09144 kilometre (d) 1.0936 kilometre 68. Which of the following is smallest unit (a) Millimetre (b) Angstrom (c) Fermi (d) Metre 69. Which one of the following pairs of quantities and their units is a proper match (a) Electric field – Coulomb / m (b)Magnetic flux – Weber (c) Power – Farad (d)Capacitance – Henry 70. The units of modulus of rigidity are (a) N−m (b) N/m (c) 2 N−m (d) 2 N/m 71. The unit of absolute permittivity is (a) Fm (Farad-meter) (b) −1 Fm (Farad/meter) (c) −2 Fm (Farad/ 2 metre ) (d) F (Farad) (e) None of these 72. Match List-I with List-II and select the correct answer using the codes given below the lists List-I List-II I. Joule A. Henry  Amp/sec II. Watt B. Farad  Volt III. Volt C. Coulomb  Volt IV. Coulomb D. Oersted  cm E. Amp  Gauss F. 2 Amp  Ohm Codes: (a) I − A,II − F,III − E,IV − D (b) I −C,II − F,III − A,IV − B (c) I −C,II − F,III − A,IV − E (d) I − B,II − F,III − A,IV −C 73. Which relation is wrong (a) 1 Calorie = 4.18 Joules (b) Å m 10 1 10 − = (c) MeV Joules 13 1 1.6 10 − =  (d) Newton Dynes 5 1 10 − = 74. If 2 x = at + bt , where x is the distance travelled by the body in kilometres while t is the time in seconds, then the units of b are (a) km/s (b) km−s (c) 2 km/s (d) 2 km−s 75. The equation       + 2 V a P (V − b) constant. The units of a are (a) 5 Dyne  cm (b) 4 Dyne  cm (c) 3 Dyne/cm (d) 2 Dyne/cm 76. Which of the following quantity is expressed as force per unit area (a) Work (b) Pressure (c) Volume (d) Area 77. Match List-I with List-II and select the correct answer by using the codes given below the lists List-I List-II (a) Distance between earth and stars 1. Microns (b) Inter-atomic distance in a solid 2. Angstroms (c) Size of the nucleus 3. Light years (d) Wavelength of infrared laser 4. Fermi 5. Kilometres Codes a b c d a b c d (a) 5 4 2 1 (b) 3 2 4 1 (c) 5 2 4 3 (d) 3 4 1 2 78. Unit of impulse is (a) Newton (b) kg−m (c) kg−m/s (d) Joule 79. Which is not a unit of electric field (a) −1 NC (b) −1 Vm (c) −1 JC (d) −1 −1 JC m 80. The correct value of C o 0 on the Kelvin scale is (a) 273 .15K (b) 272 .85 K (c) 273 K (d) 273 .2 K 81. 'Torr' is the unit of (a) Pressure (b) Volume (c) Density (d) Flux 82. Which of the following is a derived unit