To determine the relative permeability of paramagnetic FeCl3 at different temperatures, we can use the relationship between susceptibility and temperature. The susceptibility (χ) of paramagnetic materials is typically inversely proportional to temperature, following Curie's Law. This law states that the susceptibility is proportional to the inverse of the absolute temperature (T), which can be expressed mathematically as:
Understanding Curie's Law
Curie's Law can be formulated as:
Where:
- χ is the magnetic susceptibility.
- C is the Curie constant, which is specific to the material.
- T is the absolute temperature in Kelvin.
Given Data
From your question, we know:
- χ at 27°C (300 K) = 3 × 10-3
- We need to find χ at 200 K and 500 K.
Calculating the Curie Constant
First, we can calculate the Curie constant (C) using the susceptibility at 300 K:
- C = χ × T = (3 × 10-3) × 300 = 0.9
Finding Susceptibility at Different Temperatures
Now, we can use this constant to find the susceptibility at 200 K and 500 K:
At 200 K:
- χ200 = C / T = 0.9 / 200 = 0.0045
At 500 K:
- χ500 = C / T = 0.9 / 500 = 0.0018
Calculating Relative Permeability
The relative permeability (μr) of a material is related to its susceptibility by the formula:
Relative Permeability at Different Temperatures
Now, we can calculate the relative permeability at both temperatures:
At 200 K:
- μr,200 = 1 + χ200 = 1 + 0.0045 = 1.0045
At 500 K:
- μr,500 = 1 + χ500 = 1 + 0.0018 = 1.0018
Summary of Results
In summary, the relative permeability of paramagnetic FeCl3 at the specified temperatures is:
- At 200 K: μr ≈ 1.0045
- At 500 K: μr ≈ 1.0018
This demonstrates how the magnetic properties of materials can change with temperature, reflecting the fundamental principles of magnetism in paramagnetic substances.