Question

The magnetic flux per unit area of magnetic field is known as :
A.Tesla
B.Weber
C.Weber.m
D.Gauss

Answer 1

Hint: In this question, students need to know the S.I. unit of Magnetic field (B) that is magnetic flux per unit area. Mathematically, magnetic field is given by:
\[\text{B=}\dfrac{\text{ }\!\!\Phi\!\!\text{ }}{\text{A}}\] where, Ф is magnetic flux and A is the area through which magnetic lines of force are passing.

Complete answer:
When the magnetic flux is uniformly distributed over an area A, then in that case we define magnetic flux density (B), as the magnetic flux (Ф) per unit area (A).
 Magnetic field is the measure of magnetic flux per unit area.
i.e., \[\text{B=}\dfrac{\text{ }\!\!\Phi\!\!\text{ }}{\text{A}}\] (when area A is perpendicular to magnetic flux Ф)
On the basis of this relation, magnetic flux per unit area of magnetic field is given by
\[\text{1 tesla = 1}\dfrac{\text{weber}}{{{\text{m}}^{2}}}\]

Hence, the correct option is A, i.e., Tesla.

Additional Information:
One tesla is equal to one weber per square meter. The unit was announced in 1960 by the General Conference on Weights and Measures and is named in the honour of Nikola Tesla.
There is one more thing to understand, that the difference between magnetic field strength H and the magnetic induction B. In practice, people almost always call B, the magnetic field, which is because the reason that the term ‘induction’ suggests an induced magnetic moment. Since an induced magnetic moment is usually not in evidence, so the term induction is felt to be confusing. That is why people call magnetic induction a magnetic field.

Note:
Students should understand the meaning of all the basic terms related to magnetism such as: magnetic field or magnetic induction (B), magnetic field strength (H), magnetic flux (Ф) etc. so that they cannot confuse among these terms. In this way students can easily write formulae for the same and will be able to find units instantly.