Concept:The magnetic field (magnetic flux density) is measured in tesla (T) in the SI system. Tesla is the standard unit for magnetic field strength.
Explanation:Step 1: The SI unit for magnetic field (B) is the tesla (T).
Step 2: One tesla equals one weber per square meter:
1Â T=1Â Wb/m2.
Step 3: It is named after Nikola Tesla, who contributed to electromagnetism.
Step 4: Other units: gauss (CGS system) where
1Â T=10,000Â G, and oersted (for magnetizing force).
Step 5: Common examples: Earth's magnetic field is about 25–65 μT, an MRI machine uses 1.5–3 T, and a neodymium magnet is around 1 T.
Step 6: Among the given options, only tesla is the correct unit. Cobalt is a metal, ampere measures current, and ohm measures resistance.
Answer:D. Tesla