Concept:Magnetic flux is defined as the dot product of the magnetic field and the area vector. Its SI unit is the Weber (Wb).
Formula:$$ \Phi = B \cdot A $$
Solution:- Start with the units: \( \text{Wb} = \text{Tesla} \times \text{m}^2 \).
- Recall that \( B = \frac{F}{IL} \), meaning \( 1 \ \text{Tesla} = 1 \ \frac{\text{N}}{\text{A \cdot m}} \).
- Substitute this into the flux unit: \( \text{Wb} = \left( \frac{\text{N}}{\text{A \cdot m}} \right) \times \text{m}^2 \).
- Simplify the expression: \( \text{Wb} = \frac{\text{N \cdot m}}{\text{A}} = \text{N m A}^{-1} \).
Why other options are incorrect:Option B represents an incorrect dimensional analysis where the meter squared is not fully canceled. Option C is the unit for torque or work (Joule). Option D is dimensionally nonsensical for flux.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.