NEETPhysicsMagnetic Effects of Current
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The magnetic field inside a solid cylindrical conductor carrying a steady uniform current increases linearly with the distance from its axis. Reason (R): The current enclosed by an Amperian loop of radius r ( r In the light of the above statements, choose the most appropriate answer from the option
Options
- ABoth Assertion (A) and Reason (R) are correct but Reason (R) is not the correct explanation for Assertion (A).
- BBoth Assertion (A) and Reason (R) are correct and Reason (R) is the correct explanation for Assertion (A).
- CAssertion (A) is correct but Reason (R) is incorrect.
- DAssertion (A) is incorrect but Reason (R) is correct.
Correct answer
B. Both Assertion (A) and Reason (R) are correct and Reason (R) is the correct explanation for Assertion (A).
Step-by-step solution
By Ampere's Law, B d l = ₀ I_ enclosed . For a solid cylindrical conductor of radius R carrying a steady uniform current I , the current density is J = I R^2 . For an Amperian loop of radius r ( r Applying Ampere's Law for this loop: B(2 r) = ₀ I ( r^2 R^2 ) B = ( ₀ I 2 R^2 ) r This shows that the magnetic field B is directly proportional to r , meaning it increases linearly with the distance from the axis. This makes the Assertion (A) correct. Since the r^2 dependence of the enclosed current is the exact mathemati