Law Supporting the Magnetic Effect of Electricity.
Maxwells’s Right Hand Corkscrew Rule:
If a right hand corkscrew is rotated along the direction of the current flow, then the direction of screw rotation gives the direction of the magnetic lines of force around the conductor. The direction of the magnetic field can also be determined by using the right hand grip rule (see image above).
Then comes the Biot-Savart Law:
Biot and Savart conducted many experiments to determine the factors that the generated magnetic field depends on.
The results of the experiments are summarized by their law (Biot-Savart Law).
Let us consider the current carrying conductor XY carrying current I. Consider a small element in the conductor AB=dI. P is a point at a distance r from a midpoint of AB.
According to the Biot and Savart Law, the Magnetic Induction dB at a point P due to the current flow through the element dI is:
- Directly proportional to the current (I)
- Directly proportional to the length of the element (dI)
- Directly proportional to the sine of the angle between dl and the line joining element dI and the point P (sin Θ)
Inversely proportional to the square of the distance of the point P from the element dI (1/r2).
Magnetic Induction dB (directly proportional) = ( I × dI × sinΘ ) / r2
Introducing the constant for Proportionality:
k = μ/ 4π
where k = constant of proportionality, μ = magnetic constant of the medium
So the magnetic induction produced by the small element dl is given by:
dB=μ/ 4π × ( I × dI × sinΘ ) / r2
This equation is the mathematical form of Biot-Savart Law and can measure the amount of magnetic induction dB produced due to the flow of current I through the conductor element dI.
Wikipedia Commons: Biot-Savart Law , Magnetic Field
TutorVista: Biot Savart Law Examples - Rules for Determing Direction of a Magnetic Field
Integrated Publishing: Electrical Engineer Training Series