Practice Test: Question Set - 06
1. A good electric contact material should have all of the following properties except
- (A) High resistivity
- (B) High resistance to corrosion
- (C) Good thermal conductivity
- (D) High melting point
2. In thermocouples which of the following pairs is commonly used?
- (A) Copper-constantan
- (B) Aluminium-tin
- (C) Silver-German silver
- (D) Iron-steel
3. The coils of D.C. motor starter are wound with wire of
- (A) Copper
- (B) Kanthal
- (C) Manganin
- (D) Nichrome
4. A highly conductive material must have
- (A) Highest conductivity
- (B) Lowest temperature coefficient
- (C) Good mechanical strength & corrosion resistance
- (D) All of the above
5. On which of the following factors does the resistivity of a material depend?
- (A) Resistance of the conductor
- (B) Area of the conductor section
- (C) Length of the conductor
- (D) All of the above
6. Most of the common metals have _________ structure.
- (A) Linear
- (B) Hexagonal
- (C) Orthorhombic
- (D) Cubic
7. Low resistivity materials are used in
- (A) Transformer, motor and generator windings
- (B) Transmission and distribution lines
- (C) House wiring
- (D) All above applications
8. Effect of moisture on the insulating materials is to
- (A) Decrease dielectric constant
- (B) Decrease dielectric strength
- (C) Decrease insulation resistance
- (D) All of the above
9. For germanium the forbidden energy gap is
- (A) 0.15 eV
- (B) 0.25 eV
- (C) 0.5 eV
- (D) 0.7 eV
10. Selenium is ________ semiconductor.
- (A) Extrinsic
- (B) Intrinsic
- (C) N-type
- (D) P-type
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