Units & Dimensions of Physical quantities in S.I system.
Fundamental Physical Quantities:
S.No  Fundamental Physical Quantity  Formula  Dimensional Formula  S.I Unit of physical quantity 
1.  Mass  Amount of matter in the object  M  kg 
2.  Length  L  meter  
3.  Time  T  sec  
4.  Electric current  I or A  ampere  
5.  Amount of substance  N  mole(mol  
6.  Luminous intensity  J  candela(cd)  
7.  Temperature  K or  Kelvin 
Derived Physical Quantities:
S.No  Derived Physical Quantity  Formula  Dimensional Formula  S.I Unit of physical quantity 
1.  Area  []  
2.  Volume  []  
3.  Density  []  
4.  Specific Gravity  []  No units  
5.  Frequency  []  hertz  
6.  Angle  No units  
7.  Velocity  m/sec  
8.  Speed  m/sec  
9.  Areal velocity  
10.  Acceleration  
11.  Linear momentum  kg m/sec  
12.  Force  kgm/ or Newton  
13.  Weight  w=mg  kgm/ or Newton  
14.  Moment of force/Torque/Couple  kg  
15.  Impulse  kg m/sec or Ns  
16.  Pressure  N/ or Pa  
17.  Work  Nm or Joule  
18.  Kinetic Energy  joule  
19.  Potential Energy  mgh  joule  
20.  Gravitational constant  
21.  Gravitational field strength  
22.  Gravitational Potential  
23.  Force constant (k)  
24.  Power  W or J/sec  
25.  Moment of Inertia ( I )  kg  
26.  Stress  N/ or Pa  
27.  Strain  No units  
28.  Modulus of Elasticity  N/ or Pa  
29.  Poission’s Ratio  σ =1  No units  
30.  Velocity gradient  
31.  Coefficient of dynamic viscosity  kg(or) Nsec/$latex \m^2$ (or)pascalsec (or)poiseuille  
32.  Surface Tension  ,N/m  
33.  Angular displacement ()  no Units  
34.  Angular velocity(ω)  rad/sec  
35.  Angular acceleration(α)  rad/  
36.  Angular momentum  Iω  
37.  Angular Impulse  Iω  
38.  Temperature  or K  kelvin or degree Celsius  
39.  Coefficient of linear expansion(α)  /kelvin  
40.  Specific heat  
41.  Latent heat  
42.  Entropy  
43.  Thermal capacity  
44.  Gas constant  
45.  coefficient of thermal conductivity  
46.  Pole strength  Am  
47.  Magnetic Moment  
48.  Magnetic flux  weber ; ;J/Amp  
49.  Magnetic field,magnetic flux density (B)  Tesla;  
50.  Permeability of free space  
51.  Magnetic susceptibilty also called volumetric or bulk susceptibility χ_{m}  χ_{m} = μ_{r} − 1  no units  
52.  Electric Charge  Amp sec , coul  
53.  Electric potential  Volt  
54.  E.M.F  Volt  
55.  Electric Capacity  Farad  
56.  Electric Resistance  Ohm (Ω) or volt/amp  
57.  Resistivity  Ohm mt (Ωm)  
58.  Conductivity  1/  Siemens/m  
59.  Permittivity 

farad/m  
60.  Electric conductance  Siemens (or) mhos  
61.  Electric power  Watt  
62.  Electrical Impedance(Z)  Ohm (Ω) or volt/amp  
63.  Electrical admittance  1/Z(Reciprocal of electric impedance)  Siemens (or) mhos  
64.  Self Inductance(L)  weber/amp or Henry  
65.  Boltzmann’s constant  J/kelvin  
66.  Stefan’s constant  
67.  Coefficient of friction  =,N=Normal reaction  dimension less scalar  no units 
68.  Dielectric constant  It is also called relative permittivity  dimension less  no units 
69.  Planck’s constant  J.sec (or) eV.sec  
70.  Refractive index  μ  no units  
71.  Focal length(f)  Distance between center of the lens(mirror) to its focus  L  meter 
72.  Power of a lens (P)  The reciprocal of the focal length of a lens in meters is called power of a lens; p=1/f  diaptors  
73.  Wave number  No.of waves/distance  
74.  Wave length  Length of a wave  L  meter 
Advertisements