When one applies kirchhoff loop rule the algebraic sum of the potential dropsacross the cell and resistor is zero why ? Write practical application of this law
Answers
Kirchhoff's loop rule states that the algebraic sum of the voltage differences is equal to zero. The potential drop, or change in the electric potential, is equal to the current through the resistor times the resistance of the resistor.
CONCEPT:
There are two types of Kirchoff's Laws:
• Kirchoff's first law: This law is also known as junction rule or current law (KCL). According to it the algebraic sum of currents meeting at a junction is zero i.e. Σ i = 0.
• Kirchoff's second law: This law is also known as loop rule or voltage law (KVL) and according to it "the algebraic sum of the changes in potential in complete traversal of a mesh (closed loop) is zero", i.e. Σ V = 0. This law represents "conservation of energy" as if the sum of potential changes around a closed loop is not zero, unlimited energy could be gained by repeatedly carrying a charge around a loop.
EXPLANATION:
• The algebraic sum of changes in potential around any closed loop must be zero." This statement represents Kirchhoff's Loop Rule. So option 2 is correct.
EXTRA POINTS:
• Ampere's Circuital Law: It gives the relationship between the current and the magnetic field created by it. • This law says that, the integral of magnetic field density (B) along an imaginary closed path is equal to the product of current enclosed by the path and permeability of the medium.
fB. di = pol
• Force acting on a charged particle is given by Lorentz hence it is known as Lorentz force and it is expresses F = 9
Ē - UX
× B]
Net Force acting on charge = F
Force acting on the charge due to electric field = qE
• Biot-Savart Law: The law who gives the magnetic field generated by a constant electric current is Biot-savart law.
Let us take a current carrying wire of current I and we need to find the magnetic field at a distance r from the wire then it is given by:
dB = 4! (x²) dlxr
I 4π
Where, Ho = the permeability of free space/vacuum (4π x 10 T.m/A), dl = small element of wire and = the unit position vector of the point where we need to find the magnetic field.
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