Question

Magnetic susceptibility of diamagnetic materials is of the order of (SI units):
$$\begin{gathered} \text{A}\text{. + 1}{\text{0}}^5 \\ \text{B}\text{. + 1}{\text{0}}^{-4}\text{ to }+{10}^{-2} \\ \text{C}\text{. + 1}{\text{0}}^{-5} \\ \text{D}\text{. }-{10}^{-5} \end{gathered}$$

Answer 1

Hint: Diamagnetic materials are slightly repelled when placed in an external magnetic field. They get slightly magnetized but in the opposite direction to the applied magnetic field intensity and show repulsive behaviour.

Detailed step by step solution:
Based on the magnetic behaviour in the presence of an external magnetic field, we have three types of magnetism most commonly found in the materials: Para magnetism, Diamagnetism and Ferromagnetism.

Para magnetism is characterized by the fact that these materials are slightly magnetized and attracted in the direction of an external magnetic field. Diamagnetic materials are slightly repelled in the opposite direction of an external field while ferromagnetic materials are strongly attracted in the presence of an external field.

Magnetic susceptibility is a quantity which tells us how much a material gets magnetized when placed in an external magnetic field. It is defined as the ratio of magnetization (M) produced in the material and the applied magnetic field intensity (H) on the sample. Mathematical expression for susceptibility is

$\chi ={\displaystyle \frac{B}{H}}$

Paramagnets and Ferromagnets are attracted to external fields and therefore exhibit positive magnetic susceptibility which is higher in case of Ferromagnets than paramagnets. But diamagnetic materials are slightly repelled in an external field. This means that diamagnetic materials exhibit almost zero or small negative susceptibility.

Based on this reasoning, we can say that option D is the correct answer.

Note: Diamagnetic materials have an electronic structure which produces a field in the opposite direction of the external field. These two fields repel each other leading to a negative susceptibility for diamagnetic.