Measurement

Physics:

            Simply physics is the study of properties of 

matter, energy and they're mutual 

relationship.                                                           

Matter:

           Anything which occupies volume and have a weight

Energy:

The ability of a body to do work is called energy.                                          
  
Relationship between Matter and Energy 

like Einstein mass-energy relationship E=mc*2

Measurement:

                                         Comparing something with a standard 

is called measurement.

Standard with which things are compared is called unit.

Magnitude of a physical quantity means a number 

together with a unit.

Physical Quantities:

                            Those quantities which are measured are called Physical quantities.

volume,speed,force,time,mass,temperature,electric current etc

TYPES OF PHYSICAL QUANTITIES:

                                                  There are three types of physical quantities.

(1)BASIC OR FUNDAMENTAL 
QUANTITIES:

                                                         Those physical quantities which are

 not derived from other physical quantities are called basic or fundamental 

physical quantities.

Seven type of basic or fundamental physical quantities are length, mass, time, 

temperature, amount of substance, light intensity, electric current.

LENGTH:

                 The meter is the length of a path traveled by a light in 

vacuum during a time interval of 1/299792458 of a second.

MASS:KILOGRAM:

                        The kilogram is equal to the mass of the international 

prototype of the kilogram: A piece of platinum_Iridium alloy kept at the 

International bureau of weights and measures.

TIME: SECOND(s):

                        The second is the duration of  9192631770 periods of 

radiation corresponding to the transition between two hyperfine levels of the 

ground state of cesium_133 atom.

ELECTRIC CURRENT(AMPERE):

                                               One ampere is that constant current which if 

maintained in two straight parallel conductors of infinite length, of negligible 

circular cross-section, and placed 1 meter apart in vacuum, would produce 

between those conductors of a force equal to 2+10*_7( + shows multiplication)

TEMPERATURE (KELVIN):

                             Kelvin is  1/273.16 of the thermodynamic 

temperature of the triple point of water.

AMOUNT OF SUBSTANCE(MOLE):

                                         The mole is the amount of a substance which

 contain as elementary particles as there are atoms in  0.012 kilograms of 

carbon 12.

LUMINOUS INTENSITY(CANDELA):

                                         The unit of luminous intensity is the candela.it 

is defined as the luminous intensity in the perpendicular direction of the surface

 of 1/600000 square meter of a black body radiator at the solidification 

temperature of platinum under atmospheric pressure.

(2) DERIVED QUANTITIES:

                                            Those physical quantities which are derived from 

the basic or fundamental quantities are called derived quantities.

Speed....m/s

Acceleration....m/s*2

momentum...p=mv etc

(3) SUPPLEMENTARY UNITS:

There are two supplementary units

plane angle unit  Radian(rad)

solid angle unit  steradian(sr)

CGS:

        This system is based on centimeter, Gram, and second as the fundamental units of length, mass and time.

FPS:

       This system is based on centimeter, gram and second as the fundamental units of length, mass and time. this system is called the British system of units.

in this system unit of force is taken as pound, unit of energy as foot-pound, unit of power as foot-pound/sec.

MKS:

        In this system meter, kilogram and second are taken as fundamental units of mass, length and time.