Insulators and Dielectrics Quiz

Insulators have:

• Large energy gap

• an empty conduction band

• a full valence band

• None of the above

Resistivity of electrical conductors is most effected by:

• Pressure

• Temperature

• Composition

• Ageing

Application of paper in insulating material is restricted to temperature upto:

• 50 degree centigrade

• 70 degree centigrade

• 100 degree centigrade

• 180 degree centigrade

Spark plug makes use of which of the following materials for insulation:

• Porcelin

• Slate

• Asbestos

• Glass

Effect of moisture on the insulating materials is to :

• decrease dielectric constant

• decrease dielectric strength

• decrease insulation resistance

• all of the above

Insulators are the materials in which valence electrons are bounded:

• loosely to their parent atoms

• moderately to their parent atoms

• very tightly to their parent atoms

• None of the above

A good insulating material should possess which of the following characteristic:

• High insulation resistance

• High dielectric strength

• Least thermal expansion

• all of the above

The dielectric strength of mica varies from :

• 10 to 20 KV/mm thickness

• 20 to 30 KV/mm thickness

• 30 to 40 KV/mm thickness

• 40 to 150 KV/mm thickness

Porcelain insulators are employed for insulating terminals of:

• Low voltage machine

• Medium voltage machine

• High voltage machine

• all of the above

The dielectric strength of paper is:

• 2 to 4 KV/mm thickness

• 4 to 10 KV/mm thickness

• 10 to 15 KV/mm thickness

• 15 to 20 KV/mm thickness