Magnetic units: The tesla (T) is the SI unit of magnetic flux density B, not magnetic flux Φ. True or false?
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ATrue
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BFalse
Answer
Correct Answer: False
Explanation
Introduction / Context:Clear differentiation between flux Φ and flux density B is crucial in electromagnetics. Confusing their SI units can lead to incorrect calculations in transformer core sizing, motor design, and sensor selection.
Given Data / Assumptions:
- Magnetic flux Φ measures total magnetic field passing through an area.
- Magnetic flux density B measures flux per unit area.
- SI units: weber (Wb) for Φ and tesla (T) for B.
Concept / Approach:
By definition, B = Φ / A. Therefore, tesla equals weber per square meter: 1 T = 1 Wb / m^2. Saying “tesla is the unit of magnetic flux” is incorrect; magnetic flux uses the weber. The statement in the prompt reverses these definitions.
Step-by-Step Solution:
Recall: Φ has unit weber (Wb).Recall: B has unit tesla (T) = Wb / m^2.Compare the claim “tesla is the unit of flux” with correct definitions.Since T corresponds to flux density, the claim is false.Verification / Alternative check:
Consult standard SI unit tables: Weber for flux, Tesla for flux density. Engineering texts on magnetics consistently use Wb for total flux and T for B-field magnitude.
Why Other Options Are Wrong:
- Choosing “True” propagates a common mistake and would mislabel quantities in equations like B = Φ / A.
Common Pitfalls:
Conflating B (tesla) with H (A/m) and μ (H/m), or treating “lines of flux” visualizations as units. Keep track of dimensions to avoid errors in core area or saturation calculations.
Final Answer:
False