*Principle of homogeneity According to principle of homogeneity of quantities (PHQ) only those quantities can be added or subtracted which have same physical nature. e.g. Force can’t be added in velocity, similarly or distance can’t be subtracted from time. Also according to PHQ: L + L = L and L – L = L L […]
^Rules for writing units The initial letter of a unit symbol named after a scientist is written in capital letters, however the full name begins with small letter. e.g. five newtons should be written as 5 N or 5 newtons but not as 5 n. Symbols for various units are never used in plural form. […]
^Advantages of SI system Following are the advantages of SI system: Coherent: SI system of units is coherent. i.e. any unit can be derived by simply dividing & multiplying from any seven fundamental units & two basic units. Rational: For one physical quantity only one unit is used. Absolute: Use of ‘g’ is avoided. Metric: […]
*Value in S.I units
*Some SI Derived units with special names Quantity SI unit Symbol Force newton N Work joule J Pressure, Stress pascal Pa watt W Angle radian rad Frequency hertz Hz Viscosity poiseuille Pl Torque newton meter Nm Electric charge coulomb C Electrical resistance ohm W Voltage volt V Flux (Elec. or mag) weber Wb Inductance henry […]
*One steradian One steradian (sr)is the solid angle subtended at the centre of a sphere by that surface of the sphere which is equal in area to square of the radius of the sphere.
^One radian One radian (rad) is the angle subtended at the centre of a circle by an arc of length equal to the radius of circle.
*The Seven Fundamental Quantities
*Fundamental quantities Seven physical quantities have been chosen as fundamental or base quantities these are length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity. Units of base quantities are called base units or fundamental units. Fundamental or base quantities are also known as the seven dimensions of the world.
^Numerical & unit The magnitude of a quantity doesn’t change with the change of unit. i.e. numerical & unit of a physical quantity are inversely proportional.
Our objective is to create a situation where students will find Physics interesting & the strongest subject helping them to achieve top ranks in competitive exams.
Copyright © 2021 KP Institute of Physics | Powered by RiAcub
Call 9872662552