Which of the following materials does not have covalent bonds ?
A. Organic polymers
B. Silicon
C. Metals
Electrical Engineering Materials
Super conductivity can be destroyed by_____________?
Super conductivity can be destroyed by_____________?
A. adding impurities
B. reducing temperatures
C. application of magnetic field
D. any of the above
Which of the following affect greatly the resistivity of electrical conductors ?
Which of the following affect greatly the resistivity of electrical conductors ?
A. Composition
B. Pressure
C. Size
D. Temperature
__________ is a hard solder?
__________ is a hard solder?
A. Tin-lead
B. Tin-silver-lead
C. Copper-zinc
D. None of the above
Most of the common metals have _________ structure?
Most of the common metals have _________ structure?
A. linear
B. hexagonal
C. orthorhombic
D. cubic
Addition of 0.3 to 4.5% silicon to iron ________ the electrical resistivity of iron?
Addition of 0.3 to 4.5% silicon to iron ________ the electrical resistivity of iron?
A. increases
B. decreases
C. does not change
Thermonic emission occurs in______________?
Thermonic emission occurs in______________?
A. vacuum tubes
B. copper conductors
C. ferrite cores
D. transistors
A good electric contact material should have all of the following properties except_____________?
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
_________ is an example of piezoelectric material?
_________ is an example of piezoelectric material?
A. Glass
B. Quartz
C. Corrundum
D. Neoprene
Piezoelectric materials serve as a source of ____________ ?
Piezoelectric materials serve as a source of ____________ ?
A. resonant waves
B. musical waves
C. microwaves
D. ultrasonic waves