The plot of the magnitude of $\vec B$ (magnetic field) with distance 'r' from the centre of a long straight thick wire carrying steady current I distributed uniformly across its cross-section of radius 'a' is given by:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1)
When $(r<a)$: $\vec B∝r$
When $(r>a)$: $\vec B∝\frac{1}{r}$