MCQs on Engineering Materials

Page 8 of 8. Go to page
01․ Which of the following gives materials in order of decreasing values of permeability?
Permalloy, nickel, air, water.
Cobalt, nickel, aluminium, iron.
Pure iron, silicon iron, aluminium, bismuth.
Silver, copper, aluminium, iron.

Permalloy is a high magnetic permeability and low coercivity material. Nickel is distinguished by its high resistance to corrosion and it is stable in air, water, alkalis and in a number of acids. So, if we add the air and water in the Permalloy material, it gives the decreased value of permeability because the air and water are very less permeability materials.