Magnetic Materials & Curie Law question from NEET 2005 (AIPMT)

Answer: (a)

1. Diamagnetic atom: all electrons paired, net moment $\mu_d = 0$.
2. Paramagnetic and ferromagnetic atoms have unpaired electrons, so $\mu_p \ne 0$ and $\mu_f \ne 0$.
3. So the answer is (a) $\mu_d = 0$ and $\mu_p \ne 0$.