Question

The SI unit of magnetic flux is:

• A. Tesla
• B. Weber
• C. Henry
• D. Coulomb

Hint:

Be careful not to confuse Magnetic Field with Magnetic Flux. Field strength is measured in Tesla, while total Flux over an area is measured in Weber ($1 \text{ Wb} = 1 \text{ T} \cdot \text{m}^2$).

Answer 1

The Correct Option is B

Concept: Magnetic flux ($\Phi_B$) measures the total magnetic field lines passing perpendicularly through a given surface area. It is calculated as the dot product of the magnetic field vector ($\vec{B}$) and the area vector ($\vec{A}$): \[ \Phi_B = \vec{B} \cdot \vec{A} = B A \cos\theta \]

Step 1: Evaluate the SI metrics and define the units.
Since the SI unit for the magnetic field ($B$) is the Tesla ($\text{T}$) and the SI unit for area ($A$) is the square meter ($\text{m}^2$), the derived unit for magnetic flux is: \[ 1 \text{ Unit of Magnetic Flux} = 1 \text{ Tesla} \cdot \text{m}^2 \] This composite metric ($\text{T}\cdot\text{m}^2$) is officially named the Weber (Wb) in honor of German physicist Wilhelm Eduard Weber.

Step 2: Differentiate other units listed in the choices.
To avoid confusion in future questions, let's review the other units:
• Tesla (T): The SI unit for magnetic field intensity or magnetic flux density.
• Henry (H): The SI unit for electrical inductance (both self and mutual inductance).
• Coulomb (C): The SI unit for electric charge. Therefore, the Weber is the correct unit for magnetic flux.