Question

The SI unit of magnetic flux density is
A) the Tesla
B) the Henry
C) the Volt
D) the Volt-second

Answer 1

Hint: Magnetic flux density is the ratio of the magnetic flux in a region to the area of the region. The SI unit of magnetic flux is Weber and the SI unit of area is squared metres.

Complete step by step answer:
The magnetic flux through a surface is a measurement of the number of magnetic field lines passing through the surface. Mathematically, it is defined as the surface integral of the normal component of the magnetic field passing through an area.
As mentioned in the hint, the SI unit of magnetic flux is the Weber $(Wb)$. The SI unit of area is meter squared $(m^2)$. The SI unit of magnetic flux density is the ratio of 1 Weber per 1 $m^2$ area which is also known as the Tesla
Hence the SI unit of magnetic flux density is the Tesla which corresponds to option (A).

Additional information:
Magnetic flux is usually measured with a flux meter, which contains measuring coils that evaluate the change of voltage in the measuring coils to calculate the measurement of magnetic flux according to Lenz law and Faraday’s law of electromagnetic induction.

Note: In the SI unit system, 1 Tesla is defined as the magnetic field intensity which generates one Newton of force per ampere of current per meter of conductor. Since the magnitude of Tesla is very large for day to day magnetic objects around us, the magnetic flux density is often mentioned in milli-teslas and micro-teslas however the SI unit is defined as the Tesla.