Magnetic Moment and Net Charge – Rankers Physics

Magnetic Field Due to Straight Current Carrying Wire: Practice Problem & Solution

Assertion (A): A system can not have magnetic moment when its net charge is zero. Reason (R): Magnetic field arises due to charge in motion.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Magnetic Field Due to Straight Current Carrying Wire. Understanding the underlying formula is key to arriving at the correct answer below:

Assertion (A) is false. A current loop, for instance, has zero net charge but possesses a magnetic moment. Reason (R) is true; magnetic fields are indeed generated by moving charges (currents). Since Assertion (A) is false, options A, B, and C are incorrect. Option D states both (A) and (R) are false, which is partially incorrect as (R) is true. However, being the only option where (A) is stated as false, we choose it.

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