DEFINITIONS
 
 

COULOMB

 

    It is SI unit of electric charge. One coulomb (1C) of charge being that quantity of charge which when     placed one meter from an identical charge in vacuums repels it with a force of 8.99 x 109 N.

INSULATORS
 
    Insulators are those materials, which do not allow electric charges to pass through them. In other words,     insulators are materials that do not allow electrical current to pass. In insulators electrons are tightly     bounded to their atoms. Insulators do not have free electrons.
    Examples Plastic, rubber, wood, glass etc.
CONDUCTOR
 
    Conductors are those materials, which allow electric charges to pass through them. In other words,         conductors are materials that allow electric current to pass. In conductors electrons are loosely bounded     to atoms. Conductors have free electrons.
    Examples:
    Copper, Gold, Aluminum, Silver etc.
ELECTRIC FIELD
 
    Space or region surrounding a charge or charged body within which another charge experiences some     electrostatic force of attraction or repulsion when placed at a point is called Electric Field.
ELECTRIC INTENSITY
 
    It is the strength of electric field at a point. Electric intensity at a point is defined as the force     experienced per unit positive charge at a point placed in the electric field.
    Mathematically,
E=F/q
    It is a vector quantity. It has the same direction as that of force.
    Units
    N/C or Volt/m
E=1/4pe x q/r2

ELECTRICAL POTENTIAL

 
    Electric potential at a point is defined as the amount of work done in moving unit positive charge against      the direction of electric field from a point to that point.

Electrical potential = work done/charge
or
U=work/q
    unit of electric potential in SI system is Volt .
                                                                        1 volt = 1 Joule/coulomb
VOLT
 
    Unit of electric potential and potential difference in SI system is called Volt.
It is defined as
"in an electric field potential b/w two points is 1 volt if the amount of work
done in moving 1 Coulomb charge from one point to another point is 1 Joule."
POTENTIAL DIFFERENCE
 
    Potential difference b/w two points A and B is equal to the amount of work done by moving a unit positive     charge from point A to point B against the electric field
   VB-VA=VAB
or
VAB= (work)AB/q
    Unit
    Volt or Joule/Coulomb
ELECTRIC CURRENT
 
    The rate of flow of electric charge through a cross section of a conductor is called Electric Current or     Electric charge passes through a cross section of a conductor is called Electric Current.
    It is denoted by I.
FORMULA
 
I = Q/t
UNITS
 
    Ampere in SI system.
OTHER UNITS
 
    mA (milli Ampere) = 10-3A
    m A (micro Ampere) = 10-6A
AMPERE
 
    If one coulomb of electric charge passes through a cross section of a conductor in one second, the     amount of current passes through it is called Ampere. 1A = 1c/1sec.
RESISTANCE
 
    opposition offered by the atoms of a conductor in the flow of electric current is called Resistance. It is a     hurdle in the flow of electric current. Different substances have different resistance. Resistance of a     conductor increases with the increase in temperature.
SYMBOL
 
    It is denoted by R.
UNIT
 
    Ohm  
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