Identify the material that will not show a hysteresis loopa.Cobaltb.Leadc.Titanium

The material that will not show a hysteresis loop is Lead.

Here's why:

A hysteresis loop is typically observed in ferromagnetic materials. This loop illustrates the relationship between the induced magnetic field (B) in a material and the external magnetic field strength (H).

1. Cobalt: It is a ferromagnetic material. Ferromagnetic materials like cobalt have a strong attraction to magnetic fields and are able to become permanently magnetized. Hence, Cobalt will show a hysteresis loop.

2. Lead: It is not a ferromagnetic material, but rather it is diamagnetic. Diamagnetic materials are repelled by a magnetic field. They do not retain any magnetization in the absence of an externally applied magnetic field. Hence, Lead will not show a hysteresis loop.

3. Titanium: It is paramagnetic. Paramagnetic materials have a small, positive susceptibility to magnetic fields. These materials are slightly attracted to a magnetic field and the material does not retain the magnetic properties when the external field is removed. However, the magnetic behavior of Titanium is complex and can show a hysteresis loop under certain conditions.

So, out of Cobalt, Lead, and Titanium, Lead is the material that will not show a hysteresis loop.