This is in continuation with UNITS AND DIMENSIONS CONCEPTS PART ONE. Going through that post fist will give you more comfort in understanding the present post.
RULES FOR WRITING UNITS:
1. Symbols for a unit named after a scientist should have a capital letter. eg:N for newton, W for watt, A for ampere.
2. Full names of the units,even when they are named after a scientist should not be written with a capital letter. Eg: newton, watt, ampere, metre.
3. Units should be written either in full or in agreed symbols only.
4. Units do not take plural form.
Eg: 10kg but not 10 kgs, 20W but not 20 Ws 2A but not 2As
5. No full stop or punctuation mark should be used within or at the end of symbols for units.
Eg: 10W but not 10W.
DIMENSIONS OF PHYSICAL QUANTITY:
1.Dimensions: Dimensions of a physical quantity are the powers to which the fundamental units are to be raised to obtain one unit of that quantity.
2.Dimensional Formula : An expression showing the powers to which the fundamental units are to be raised to obtain one unit of the derived quantity is called Dimensional formula of that quantity.
3. Dimensional Constants: The physical quantities which have dimensions and have a fixed value are called dimensional constants.
Eg: Gravitational Constant (G), Planck's Constant (h), Universal gas constant (R), Velocity of light in vacuum (c) etc.,
4. Dimensionless constants: Dimensionless quantities are those which do not have dimensions but have a fixed value.
(a): Dimensionless quantities without units.
Eg: Pure numbers, π , e, Sin θ , Cos , tan ......etc.,
(b) Dimensionless quantities with units.
Eg: Angular displacement - radian, Joule's constant- joule/calorie, etc.,
5. Dimensional variables: Dimensional variables are those physical quantities which have dimensions and do not have fixed value.
Eg: velocity, acceleration, force, work, power... etc.
6. Dimensionaless variables: Dimensionless variables are those physical quantities which do not have dimensions and do not have fixed value.,
Eg: Specific gravity, refractive index, Coefficient of friction, Poisson's Ratio etc.,
PHYSICAL QUANTITIES HAVING SAME DIMENSIONAL FORMULA:
RULES FOR WRITING UNITS:
1. Symbols for a unit named after a scientist should have a capital letter. eg:N for newton, W for watt, A for ampere.
2. Full names of the units,even when they are named after a scientist should not be written with a capital letter. Eg: newton, watt, ampere, metre.
3. Units should be written either in full or in agreed symbols only.
4. Units do not take plural form.
Eg: 10kg but not 10 kgs, 20W but not 20 Ws 2A but not 2As
5. No full stop or punctuation mark should be used within or at the end of symbols for units.
Eg: 10W but not 10W.
DIMENSIONS OF PHYSICAL QUANTITY:
1.Dimensions: Dimensions of a physical quantity are the powers to which the fundamental units are to be raised to obtain one unit of that quantity.
2.Dimensional Formula : An expression showing the powers to which the fundamental units are to be raised to obtain one unit of the derived quantity is called Dimensional formula of that quantity.
3. Dimensional Constants: The physical quantities which have dimensions and have a fixed value are called dimensional constants.
Eg: Gravitational Constant (G), Planck's Constant (h), Universal gas constant (R), Velocity of light in vacuum (c) etc.,
4. Dimensionless constants: Dimensionless quantities are those which do not have dimensions but have a fixed value.
(a): Dimensionless quantities without units.
Eg: Pure numbers, π , e, Sin θ , Cos , tan ......etc.,
(b) Dimensionless quantities with units.
Eg: Angular displacement - radian, Joule's constant- joule/calorie, etc.,
5. Dimensional variables: Dimensional variables are those physical quantities which have dimensions and do not have fixed value.
Eg: velocity, acceleration, force, work, power... etc.
6. Dimensionaless variables: Dimensionless variables are those physical quantities which do not have dimensions and do not have fixed value.,
Eg: Specific gravity, refractive index, Coefficient of friction, Poisson's Ratio etc.,
PHYSICAL QUANTITIES HAVING SAME DIMENSIONAL FORMULA:
- Distance, Displacement, radius light year wavelength, radius of gyration (L) .
- Speed, Velocity, Velocity of light .
- acceleration ,acceleration due to gravity, intensity of gravitational field, centripetal acceleration .
- Impulse, Change in momentum
- Force, Weight, Tension, Thrust
- Work, Energy, Moment of force or Torque,
- Moment of couple
- Force constant, Surface Tension, Spring constant, Energy per unit area
- Angular momentum, Angular impulse, Plank's constant
- Angular velocity, Frequency, Velocity gradient,Decay constant, rate of disintigration
- Stress, Pressure, Modulus of Elasticity, Energy density
- Latent heat, Gravitational potential
- Specific heat, Specific gas constant
- Thermal capacity, Entropy, Boltzman constant,Molar thermal capacity,
- wave number, Power of a lens, Rydberg constant
- Time, RC, L R ,
- Power, Rate of dissipation of energy,
- Intensity of sound, Intensity of radiation
- Expansion coefficient, Temperature coefficient of resistance
- Electric potential, potential difference,electromotive force
- Intensity of magnetic field, Intensity of magnetization
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