In order to minimise loss due to hysteresis, the magnetic material should have high retentivity. high resistivity. large B-H loop area. low hysteresis coefficient. TRUE ANSWER : ? YOUR ANSWER : ?
________ is the most detrimental impurity in the magnetic materials Carbon. Oxygen. Nitrogen. Sulphur. TRUE ANSWER : ? YOUR ANSWER : ?
Positive magnetostriction exists when dipoles are attract each other. both are correct. none of above. dipoles are repel other. TRUE ANSWER : ? YOUR ANSWER : ?
Which of the following is the example for piezo-electric material ? Potassium niobate None of these Lead zirconate titanate Copper TRUE ANSWER : ? YOUR ANSWER : ?
Why diamond is very hard ? Because of covalent solid Because of large cohesive energy Because of high melting point None of these TRUE ANSWER : ? YOUR ANSWER : ?
How many valence electrons would be found in an atom with the atomic number of 51? 8. none of above. 51. 5. TRUE ANSWER : ? YOUR ANSWER : ?
Which of the following gives materials in order of decreasing values of permeability? Silver, copper, aluminium, iron. Cobalt, nickel, aluminium, iron. Pure iron, silicon iron, aluminium, bismuth. Permalloy, nickel, air, water. TRUE ANSWER : ? YOUR ANSWER : ?
The magnetisation and applied field in ferromagnetic materials are related parabolically. linearly. non linearly. sinusoidally. TRUE ANSWER : ? YOUR ANSWER : ?
Choose the best suitable of Diamagnetic : Paramagnetic:: Iron : Steel. Permalloy : Super-alloy. Water : Air. Nickel : Cobalt. TRUE ANSWER : ? YOUR ANSWER : ?
Permanent magnets are used in generators. motors. all of above. loud speakers. TRUE ANSWER : ? YOUR ANSWER : ?