File Name: measurement units and dimensions in physics .zip
The units that can be expressed independently are called fundamental or base units. For example- mass is expressed in kilogram, length in metre, and time in second respectively are fundamental units. The units for which a combination of the fundamental units is called derived units. The base units for length, mass and time in unit systems are:. CGS System: centimetre, gram and second. FPS System: foot, pound and second. MKS System: metre, kilogram and second.
Till class X we have studied many physical quantities eg. Physical quantities are of three types. All the basic quantities are chosen such that they should be different, that means independent of each other. These are the elementary quantities in our planet thats why chosen as basic quantities. In fact any set of independent quantities can be chosen as basic quantities by which all other physical quantities can be derived. Can be chosen as basic quantities on some other planet, these might also be used as basic quantities.
In this article, we shall study the concept of dimensions of physical quantities and to find dimensions of given physical quantity. Dimensions of Physical Quantity:. The power to which fundamental units are raised in order to obtain the unit of a physical quantity is called the dimensions of that physical quantity. Dimensions of physical quantity do not depend on the system of units. Mass, length and time are represented by M, L, T respectively.
In engineering and science , dimensional analysis is the analysis of the relationships between different physical quantities by identifying their base quantities such as length , mass , time , and electric charge and units of measure such as miles vs. The conversion of units from one dimensional unit to another is often easier within the metric or SI system than in others, due to the regular base in all units. Dimensional analysis, or more specifically the factor-label method , also known as the unit-factor method , is a widely used technique for such conversions using the rules of algebra. Commensurable physical quantities are of the same kind and have the same dimension, and can be directly compared to each other, even if they are originally expressed in differing units of measure, e. Incommensurable physical quantities are of different kinds and have different dimensions, and can not be directly compared to each other, no matter what units they are originally expressed in, e.
Physics is a quantitative science, based on measurement of physical quantities. Certain physical quantities have been chosen as fundamental or base quantities. The fundamental quantities that are chosen are Length, Mass, Time, electric current, thermodynamic temperature, amount of substance, and luminous intensity. Each base quantity is defined in terms of a certain basic arbitrarily chosenbut properly standardised reference standard called unit such as metre,kilogram,second,ampere,kelvin,mole,and candela. The units for the fundamental base quantities are called fundamental or base units and two supplementary units in relation to quantities plane angle and solid angle radian, Ste radian.. Other physical quantities derived from the base quantities can be expressed as a combination of the base units and are called derived units.
It is must to measure all Physical quantities so that we can use them. Ph: UNIT & DIMENSION. 3. Physics: Physics is the study of the laws of.
The thumbnail image is of the Whirlpool Galaxy, which we examine in the first section of this chapter. Galaxies are as immense as atoms are small, yet the same laws of physics describe both, along with all the rest of nature—an indication of the underlying unity in the universe. In this text, you learn about the laws of physics.
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