Concept:Magnetic flux depends only on the area's magnitude, the magnetic field strength, and their relative angle, not the geometrical perimeter or shape.
Formula:$$ \Phi = B \cdot A $$
Solution:- The formula for flux \( \Phi = BA \cos(\theta) \) requires only the numerical value of the Area \( A \).
- Whether the \( 1 \ \text{m}^2 \) area is cut into a circle, a long rectangle, or a square, the total number of field lines intersecting that boundary remains identically the same (assuming uniform field and orientation).
- Therefore, the flux is entirely independent of the surface's 2D shape.
Why other options are incorrect:Options A, B, and C incorrectly imply that geometry affects the counting of field lines over a flat plane, which is topologically false.
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