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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Kirchoff's laws | current electicity | physics

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•Kirchoff's First law (kcl):-

It states that the algebraic sum of current meeting or leaving a point is always zero. It is also called functional rule.

•Example:-

Consider a point N in an electric circuits in which current I1, I2, I3, i4 and I5 passing through resistances.
Applying Kirchhoff's law
I1+I2-I3+I4-I5=0


•Kirchoff's second Law (kvl) :-

In a loop the algebraic sum of the emf's is equal to the algebraic sum of products of the resistance and the respective current passing through it. It is also called kirchoff's voltage law. 

•Example :-




•Some important board exam level question answers :-


Q. 1) Write Kirchhoff's First law  ?

Ans:- It states that the algebraic sum of current meeting or leaving a point is always zero. It is also called functional rule.


Q. 2) Write Kirchhoff's second Law  ?

Ans:- In a loop the algebraic sum of the emf's is equal to the algebraic sum of products of the resistance and the respective current passing through it. It is also called kirchoff's voltage law.






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 •  Electric lines of force        (Electrostatics)  1. The electric lines of force start from positive charge and end at negative charge.      2.  The lines of forces originate or terminate at a surface is always right angle to that surface. 3. The lines of forces never intersect each other. 4. The electric lines of force do not pass through a conductor. 5.Like charges repel each other wherever unlike charges attracted each other  • Some important Question Answer From Board level Exams:- Q. 1) Why electric field lines of force cannot intersect each other?   Ans:- This is because at the point of intersection, two tangent would have to be drawn to the lines of Force. Therefore would be two directions of electric intensity at the same point, which is not possible.  Q. 2) Write Two properties of electric field lines of force?  Ans:-    1. The lines of forces ...
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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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