current | resistivity | Current electricity | ohm law | electric current | physics

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Current electricity and ohm's law(Current electricity) :- •What is current? Rate of flow of electric charge with time through any cross section of a wire is called current. It is denoted by I . Thus if charge "dq" flows through a wire in small time "dt" then electric current through wire is given by :                                             I=dq/dt  1 ampere = 1coulomb/1 second  1A=C/s •Ampere :-                                                           The current Through a wire is called one ampere if one coulomb charge is flow through Any cross section of wire in one second   •Ohm's law:- Ohm’s principal discovery was that the amount of electric current through a metal conductor...
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Electric field (electrostatic) | electostatic | physics

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Electric field (Electrostatics) 

. The space around a charge in which any other charge is acted upon by an electrostatic force is called electric field of charge .
                  E = F/q.
                 We know that, 
         F = k Qq. /r2
          
Therefore 
         
     E = k Qq. /r2 *1/q. 
             
      E =kQ/r2 

  The charge "Q" due to which electric field is set up is called source charge and the other charge "q." which experience electrostatic force in the electric field is called test charge .

Electric field intensity :-


The electric field intensity or electric field strength at a point due to a source charge may be defined as the electrostatic force per unit positive charge acting on a vanishingly small positive test charge placed at that point .

 E = F/q.
Limit at q. =0

•Some Boards exam level question Answers:-


Q. 1) Give two units of electric field at a point? 

Ans:-  1. newton per coulomb (N/C)
            2. Volts per meter (V/m)


Q. 2) Define electric field at a point. What are its units? 

Ans:- Electric field at a point is defined as the electrostatic force per unit charge acting on a vanishingly small test charge at that point.
It's unit's are-
   1. newton per coulomb (N/C)
   2. Volts per meter (V/m)


Q. 3) Is the electric field is a scalar or vector quantity? 

Ans:- It is a vector quantity. 


Q. 4) What is the direction of electric field intensity vector E ?

Ans:- It's direction is in direction of the force acting on unit +ve charge. 

Video explaining :-


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Current electricity and ohm's law(Current electricity) :- •What is current? Rate of flow of electric charge with time through any cross section of a wire is called current. It is denoted by I . Thus if charge "dq" flows through a wire in small time "dt" then electric current through wire is given by :                                             I=dq/dt  1 ampere = 1coulomb/1 second  1A=C/s •Ampere :-                                                           The current Through a wire is called one ampere if one coulomb charge is flow through Any cross section of wire in one second   •Ohm's law:- Ohm’s principal discovery was that the amount of electric current through a metal conductor...
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