Which of the following is a semiconductor material ?
A. Phosphorous
B. Rubber
C. Silicon
D. Aluminium
Electrical Engineering Materials
Due to which of the following reasons copper and aluminium are not used for heating elements ?
Due to which of the following reasons copper and aluminium are not used for heating elements ?
A. Both have great tendency for oxidation
B. Both have low melting point
C. Very large length of wires will be required
D. All of the above
Which of the following materials is the best conductor of electricity ?
Which of the following materials is the best conductor of electricity ?
A. Tungsten
B. Aluminium
C. Copper
D. Carbon
Thermocouples are mainly used for the measurement of_____________?
Thermocouples are mainly used for the measurement of_____________?
A. temperature
B. resistance
C. eddy currents
D. coupling co-efficient
The conduction of electricity, in semiconductors, takes place due to movement of______________?
The conduction of electricity, in semiconductors, takes place due to movement of______________?
A. positive ions only
B. negative ions only
C. positive and negative ions
D. electrons and holes
is the property of absorbing moisture from atmosphere_____________?
is the property of absorbing moisture from atmosphere_____________?
A. Solubility
B. Viscosity
C. Porosity
D. Hygroscopicity
Substances whose specific resistance abruptly decreases at very low temperature are called___________?
Substances whose specific resistance abruptly decreases at very low temperature are called___________?
A. insulators
B. conductors
C. semiconductors
D. superconductors
Which of the following is an advantage of stranded conductor over equivalent single conductor ?
Which of the following is an advantage of stranded conductor over equivalent single conductor ?
A. Less liability to kink
B. Greater flexibility
C. Less liability to break
D. All of the above
Copper, even though costly, finds use in the windings of electrical machines because_____________?
Copper, even though costly, finds use in the windings of electrical machines because_____________?
A. copper points offer low contact resistance
B. copper can be easily soldered and welded
E. copper windings are less bulky and the machines become compact
D. all of the above
Which of the following materials is used for making coils of standard resistances ?
Which of the following materials is used for making coils of standard resistances ?
A. Copper
B. Nichrome
C. Platinum
D. Manganin