Question Analysis: Assertion (A) and Reason (R) type question.

Step 1 (Governing Law & Conceptual Definition): [0.5 Mark]

The magnetic moment of an atom arises from the orbital motion and spin of its electrons. According to the principle of superposition, the net magnetic moment of an atom is the vector sum of the magnetic moments of all its constituent electrons: $$\vec{\mu}_{net} = \sum \vec{\mu}_i$$ In many atoms (e.g., noble gases), the electrons are paired such that their spins and orbital motions cancel each other out, resulting in a net magnetic moment of zero ($\vec{\mu}_{net} = 0$). Thus, the statement that "all atoms have a net magnetic moment" is False.

Step 2 (Step-by-Step Logical Deduction): [0.25 Mark]

A current loop of area $\vec{A}$ carrying current $I$ always behaves as a magnetic dipole with a magnetic moment given by: $$\vec{\mu} = I \vec{A}$$ Since any closed current loop produces a magnetic field equivalent to a magnetic dipole at large distances, the statement that "a current loop does not always behave as a magnetic dipole" is False.

Step 3 (Final Concluded Answer): [0.25 Mark]

Since both Assertion (A) and Reason (R) are incorrect statements, the correct option is:

Assertion (A) is false and Reason (R) is false.

💡 EL10 Concept Insight:

Think of an atom like a tiny solar system; if the electrons are perfectly balanced in pairs, their magnetic "pulls" cancel out to zero, which is why not all atoms are magnets. Also, any loop of wire with electricity flowing through it will always act like a tiny bar magnet, so the claim that it doesn't is simply incorrect.