Directly as the cross-sectional area of magnetic core
Directly as square of number of turns
Inversely as the length of the iron path
All of above
Answer is Wrong!
Answer is Right!
The inductance of a coil varies directly as the square of the number of turns, directly as the cross-sectional area of the magnetic core, and inversely as the length of the iron path.
The inductance of a coil is a measure of its ability to store energy in a magnetic field. The more turns a coil has, the stronger the magnetic field it will create. The larger the cross-sectional area of the magnetic core, the more magnetic flux can be stored in the core. The shorter the length of the iron path, the less eddy currents will be generated in the core, which will reduce losses and increase the inductance of the coil.
Therefore, the correct answer is D. All of above.