Q. The magnetic flux density $B\ at\ a\ distance\ r\ $from a long straight rod carrying a steady current varies with r as shown in figure.
A) [image:4_image55.emf]
B) [image:4_image56.emf]
C) [image:4_image57.emf]
D) [image:4_image58.emf]
Explanation
(d) Magnetic flux inside rod $B \propto r\ $and outside the rod $B \propto \frac{i}{r}\ .$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.