Which of the following material is not a semiconductor ?
A. Silica
B. Germanium
C. Selenium
D. Gallium-arsenide
Electrical Engineering Materials
The number of atoms per unit cell in B.C.C. structure is_____________?
The number of atoms per unit cell in B.C.C. structure is_____________?
A. 1
B. 2
C. 4
D. 8
In a crystal, an atom vibrates at a frequency determined by_______________?
In a crystal, an atom vibrates at a frequency determined by_______________?
A. the heat content of the crystal
B. the temperature of the crystal
C. the stiffness of the bonds it makes with neighbors
The conductivity of a metal is determined by____________?
The conductivity of a metal is determined by____________?
A. the electronic concentration and the mobility of the free electrons
B. the number of valence electrons per atom
C. either (A) or (B)
D. none of the above
Due to which of the following reasons aluminium does not corrode in atmosphere ?
Due to which of the following reasons aluminium does not corrode in atmosphere ?
A. Aluminium is a noble metal
B. Atmospheric oxygen can only diffuse very slowly through the oxide layer which is formed on the surface of aluminium
C. No reaction with oxygen occurs ft Any of the above
The resistivity of a metal is a function of temperature because_____________?
The resistivity of a metal is a function of temperature because_____________?
A. the amplitude of vibration of the atoms varies with temperature
B. the electron density varies with temperature
C. the electron gas density varies with temperature
Total number of crystal systems is____________?
Total number of crystal systems is____________?
A. 2
B. 4
C. 7
D. 12
A carbon resistor contains_____________?
A carbon resistor contains_____________?
A. carbon crystals
B. solid carbon granules
C. pulverized coal
D. finely divided carbon black
In graphite, bonding is____________?
In graphite, bonding is____________?
A. covalent
B. metallic
C. Vander Waals
D. Vander Waals and covalent
Non-linear resistors______________?
Non-linear resistors______________?
A. produce harmonic distortion
B. follows Ohm’s law at low temperatures only
C. result in non-uniform heating
D. none of the above