A sample of paramagnetic salt contains 2.0 × 1024 atomic dipoles each of dipole moment 1.5 × 10–23 J T–1. The sample is placed under a homogeneous magnetic field of 0.64 T and cooled to a temperature of 4.2 K. The degree of magnetic saturation achieved is equal to 15%. What is the total dipole moment of the sample for a magnetic field of 0.98 T and a temperature of 2.8 K? (Assume Curie’s law)
Total dipole moment of the atomic dipole=n×M =2×1024×1.5×10−23=30JT−1 Magnetic saturation is achieved at 15%. M1=10015×30=4.5JT−1 When magnetic field is B2=0.98T,T2=2.8K, its total dipole moment is M2. According to Curie's Law, we have, M1M2=B1B2×T2T1 ⟹M2=10.336JT−1
